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| United States Patent Application |
20060265784
|
| Kind Code
|
A1
|
|
Hauptmann; Randal
;   et al.
|
November 23, 2006
|
Tagetes erecta MARIGOLDS WITH ALTERED CAROTENOID COMPOSITIONS AND RATIOS
Abstract
A marigold plant, a regenerable portion thereof and seed are disclosed
whose flower petals, leaves or flower petals and leaves contain one or
more of an enhanced neoxanthin plus violaxanthin ratio, an enhanced
.beta.-carotene ratio, an enhanced lycopene ratio, an enhanced
.alpha.-cryptoxanthin ratio, an enhanced phytoene ratio or an enhanced
phytofluene ratio relative to that ratio in a non-mutant marigold. A
marigold plant, a regenerable portion thereof and seed are also disclosed
whose flower petals contain zeaxanthin esters and are substantially free
of esters of both neoxanthin and violaxanthin, and wherein zeaxanthin
constitutes at least about one-half of the extractable carotenoids when
xanthophylls are assayed as alcohols. Also disclosed are methods of
preparing such plants, oleoresins and comestible materials that have such
carotenoid ratios.
| Inventors: |
Hauptmann; Randal; (Marina, CA)
; Winner; Blair L.; (Ventura, CA)
; Blowers; Alan; (St. Charles, IL)
|
| Correspondence Address:
|
WELSH & KATZ, LTD
120 S RIVERSIDE PLAZA
22ND FLOOR
CHICAGO
IL
60606
US
|
| Serial No.:
|
427250 |
| Series Code:
|
11
|
| Filed:
|
June 28, 2006 |
| Current U.S. Class: |
800/282 |
| Class at Publication: |
800/282 |
| International Class: |
A01H 1/00 20060101 A01H001/00; C12N 15/82 20060101 C12N015/82 |
Claims
1-49. (canceled)
50. An oleoresin of a Tagetes erecta marigold, said oleoresin having a
ratio of the amount of lycopene to the amount of lycopene plus lutein
that is at least about 0.1, wherein the amount of lutein is determined
after saponification.
51. An oleoresin of a Tagetes erecta marigold, said oleoresin containing
free, unesterified xanthophylls.
52-61. (canceled)
62. A Tagetes erecta marigold oleoresin whose carotenoids include
zeaxanthin esters and are substantially free of both neoxanthin and
violaxanthin esters when said oleoresin is analyzed after saponification.
63-75. (canceled)
76. The oleoresin according to claim 50 wherein ratio of the amount of
lycopene to the amount of lycopene plus lutein greater than 0.2.
77. The oleoresin according to claim 50 wherein ratio of the amount of
lycopene to the amount of lycopene plus lutein greater than 0.3.
78. The oleoresin according to claim 50 wherein ratio of the amount of
lycopene to the amount of lycopene plus lutein greater than 0.5.
79. The oleoresin according to claim 50 wherein ratio of the amount of
lycopene to the amount of lycopene plus lutein about 1.0.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of application Ser. No. 10/447,769, filed
May 29, 2003, which is a continuation-in-part of application Ser. No.
10/325,265 filed on Dec. 19, 2002, now U.S. Pat. No. 7,033,622, that was
a continuation-in-part of application Ser. No. 10/180,775 that was filed
on Jun. 26, 2002, now U.S. Pat. No. 6,784,351, that itself claimed
priority of provisional application Ser. No. 60/302,460 that was filed on
Jun. 29, 2001, whose disclosures are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a marigold plant that contains
carotenoid pigments present at other than the usual ratios. The invention
more particularly relates to a marigold plant, a regenerable portion
thereof, a hybrid or later generation whose petals, leaves or both petals
and leaves, contain an enhanced ratio of one or more carotenoid compounds
relative to lutein, and also seed that produces such a marigold plant, an
oleoresin produced from such flowers or leaves and comestible products
made using zeaxanthin and lutein. The flower petals of such a
contemplated marigold typically also contain a measurable amount of
zeta-carotene, a compound not normally found in marigold flower petals.
BACKGROUND OF THE INVENTION
[0003] Numerous epidemiological studies in various populations have shown
that consumption of substantial amounts of fruits and vegetables rich in
carotenoids can reduce the risk of acquiring several types of cancers. As
a result, scientists have been focusing on investigating the protective
effect of carotenoids such as beta-(.beta.-)carotene in prevention of
cancer, cardiovascular and eye diseases. These studies have been carried
out despite the fact that .beta.-carotene is only one of the prominent
carotenoids found in fruits and vegetables whose consumption has been
associated with health benefits. The reasons for such focus can be
attributed to the pro-vitamin A activity of .beta.-carotene and the
limited commercial availability of other prominent food carotenoids.
[0004] Among the 40 to 50 carotenoids that are available from the diet and
may be absorbed, metabolized, or utilized by the human body, only 13
carotenoids and 12 of their stereoisomers are routinely found in human
serum and milk. [See Khachik et al., Anal. Chem., 69:1873-1881 (1997).]
In addition, there are 8 carotenoid metabolites and one stereoisomer in
human serum or plasma that result from a series of oxidation-reduction
reactions of three dietary carotenoids: lutein, zeaxanthin and lycopene.
These metabolites were first isolated and characterized by Khachik et al.
[See Khachik et al., Anal. Chem., 64:2111-2122 (1992).]
[0005] In another study, the ingestion of purified supplements of dietary
(3R,3'R,6'R)-lutein and (3R,3'R)-zeaxanthin was shown to not only result
in an increase in the blood levels of these compounds in humans, but also
in an increase in the concentration of their oxidative metabolites in
plasma. [See Khachik et al., J. Cellular Biochem., 22: 236-246 (1995).]
These findings provided preliminary evidence that carotenoids may
function as antioxidants in disease prevention. In addition, these
results also established the importance of non-vitamin A-active dietary
carotenoids, particularly, lutein, zeaxanthin, and lycopene.
[0006] There is increasing evidence that the macular pigment carotenoids,
lutein and zeaxanthin, may play an important role in the prevention of
age-related macular degeneration (ARMD), cataract formation, and other
light-induced oxidative eye damage. In 1985 and 1993, Bone et al.
demonstrated that the human macular pigment is a combination of lutein
and zeaxanthin, and speculated that these dietary carotenoids may play a
role in the prevention of an eye disease ARMD. [See Bone et al., Vision
Research, 25:1531-1535 (1985) and Bone et al., Invest. Ophthalmol. Vis.
Sci., 34: 2033-2040 (1993).] Further work in a case-controlled
epidemiological study in which the high consumption of fruits and
vegetables, rich specifically in lutein and zeaxanthin was correlated to
a 43 percent lower risk of ARMD later confirmed that speculation. [See
Seddon et al., J. A. Med. Assoc., 272 (18) 1413-1420 (1994).] It has also
been reported that an increased level of serum carotenoids other than
.beta.-carotene is associated with a lower incidence of heart disease.
[See Morris et al., J. Amer. Med. Assoc., 272(18):1439-1441(1994).]
[0007] Bernstein et al. identified and quantified the dietary carotenoids
and their oxidative metabolites in all tissues of the human eye and
reported that nearly all ocular structures examined with the exception of
vitreous, cornea and sclera had quantifiable levels of dietary
(3R,3'R,6'R)-lutein, zeaxanthin, their geometrical (E/Z) isomers, as well
as their metabolites, (3R,3'S,6'R)-lutein (3'-epilutein) and
3-hydroxy-beta, epsilon-caroten-3'-one. In the iris, these pigments were
thought likely to play a role in filtering p
hototoxic short-wavelength
visible light and to act as antioxidant in the ciliary body. Both
mechanisms may be operative in the retinal pigment epithelium/choroid
(RPE/choroids). [See Bernstein et al., Exp. Eye Research, 72(3):215-223
(2001].]
[0008] A study of the distribution of macular pigment stereoisomers in the
human retina identified (3S,3'S)-zeaxanthin in the adult retina,
particularly in the macula. It was proposed that dietary lutein and
zeaxanthin are transported into an individual's retina in the same
proportions found in the blood serum, although the two pigments are
present in the eye in ratios different from those found in the blood.
Thus, zeaxanthin predominates over lutein by a ratio greater than 2:1 in
the foveal region, with the macular pigment optical density dropping by a
factor of 100 and the zeaxanthin to lutein ratio reversing to about 1:2.
[See Bone et al., Invest. Ophthalmol. Vis. Sci., 29:843-849(1988).] Some
lutein is converted into the non-dietary meso-zeaxanthin primarily in the
macula. [See Bone et al., Exp. Eye Res., 64(2): 211-218 (1997).] Such
reports lend support to the critical role of ocular carotenoids, and
therefore to the importance of commercial production of dietary
carotenoids in general, and particularly lutein and zeaxanthin.
[0009] The Tagetes genus is a member of the family Compositae,
alternatively known as Asteraceae, and comprises some thirty species of
strongly scented annual or perennial herbs. Tagetes are native from
Arizona and New Mexico to Argentina. [See Hortus Third A Concise
Dictionary of Plants Cultivated in the United States and Canada,
MacMillan Publishing Company (1976).] Cultivated genera include Tagetes
erecta, commonly referred to as African marigold, Tagetes patula,
commonly referred to as French marigold, Tagetes erecta.times.patula,
commonly referred to as Triploid marigolds, and Tagetes tenuifolia also
known as Tagetes signata or signet marigold.
[0010] A marigold inflorescence is a solitary head comprised of a dense
cluster of several hundred sessile or subsessile small flowers also known
as florets. Marigolds have radiate flower heads with outer ray florets
that are ligulate or strap-shaped around the central tubular shaped disk
florets. Some forms of marigold flower heads have most of their disk
flowers transformed into ray flowers and contain few, if any, disk
flowers. Such flower heads are referred to as double-flowered.
[0011] The ray flowers or florets are often referred to as petals by lay
persons who may also refer to the flower heads as flowers. For ease of
understanding, marigold flower heads will be referred to herein as
flowers or flower heads, whereas the flower head-component flowers or
florets, stamens, stigmas and carpels will be referred to as petals.
[0012] Cultivated marigolds possess showy flowers and are useful for
ornamental purposes. In addition, the genus is recognized as a source for
natural colorants, essential oils, and thiophenes. Dried marigold petals
and marigold petal concentrates obtained from so-called xanthophyll
marigolds are used as feed additives in the poultry industry to intensify
the yellow color of egg yolks and broiler skin. [See Piccalia et al.,
Ind. Crops and Prod., 8:45-51 (1998).] The carotenoids desired in poultry
tissues are a function of their dietary concentration, because poultry do
not have the ability to synthesize carotenoids de novo. [See Balnave et
al., Asian-Australiasian J. Animal Sci., 9(5):515-517 (1996).]
[0013] Xanthophyll marigolds differ in several characteristics from
ornamental marigolds. First and foremost, xanthophyll marigolds are used
as an extractable source for carotenoids and have plant habits that
differ from ornamental marigolds. Ornamental marigolds typically grow
only about 45 to about 60 cm from the ground, whereas xanthophyll
marigolds grow to about 65 to about 70 cm from the ground. Xanthophyll
marigolds grow in a bushier habit than do ornamental marigolds, and can
be grown as row crops whereas ornamental marigolds typically cannot.
Xanthophyll marigolds are typically dark orange in color, whereas
ornamentals can be white, yellow, or orange in color, or can have mixed
colors, including mahogany colors due to the presence of anthocyanin
pigments.
[0014] The pigmenting ability of marigold petal meal resides largely in
the oxygenated carotenoid fraction known as the xanthophylls, primarily
lutein esters. [See Piccalia et al., Ind. Crops and Prod., 8:45-51
(1998).] The xanthophyll zeaxanthin, also found in marigold petals, has
been shown to be effective as a broiler pigmenter, producing a highly
acceptable yellow to yellow-orange color. [See Marusich et al., Poultry
Sci., 55:1486-1494 (1976).] Of the xanthophylls, the pigments lutein and
zeaxanthin are the most abundant in commercially available hybrids.
Structural formulas for lutein and zeaxanthin are shown below.
[0015] Each of lutein and zeaxanthin contains one hydroxyl group in each
of their terminal ring structures, so that each molecule contains two
hydroxyl groups. Lutein is believed to be biologically produced by two
separate hydroxylations of .alpha.-carotene, whereas zeaxanthin is
believed to be biologically produced by two separate hydroxylations of
.beta.-carotene.
[0016] Both .alpha.-carotene and .beta.-carotene are understood to be
formed by the action of appropriate cyclase enzymes on lycopene to first
yield .delta.-carotene or .gamma.-carotene that thereafter cyclize
further to form .alpha.-carotene or .beta.-carotene, respectively.
Lycopene, .gamma.-carotene, .alpha.-carotene and .beta.-carotene are each
hydrocarbon carotenoids that are referred to in the art as carotenes.
Thus, carotenoid pigments can be grouped into one or the other of two
families: the hydrocarbon carotenes or the oxygenated xanthophylls.
Phytoene, the first C.sub.40 carotenoid in the pathway, is a colorless
hydrocarbon. The hydrocarbon carotene pigments with the exception of
.beta.-carotene typically do not accumulate in marigold leaves or flower
parts, whereas the xanthophylls do accumulate in both leaves and flower
parts.
[0017] FIG. 1 shows a schematic representation of the biological synthesis
pathway for the production of lutein and zeaxanthin and later products
from phytoene via lycopene, .gamma.-carotene, .alpha.-carotene and
.beta.-carotene. Lutein and zeaxanthin are present in marigold petals
primarily as mono- and di-esters of fatty acids. FIG. 1 also notes
epoxide-containing later products that can arise from zeaxanthin, of
which violaxanthin is an intermediate in the abscisic acid biosynthetic
pathway.
[0018] For the feed additive industry, xanthophyll marigolds are produced
primarily in Mexico, Peru, Africa, India, China and Thailand. Modern,
commercial varieties include `Orangeade`, one of the original xanthophyll
producing varieties, and commercial improvements of `Orangeade`,
including `Deep Orangeade` having larger flowers and greater pigment
yields, and `Scarletade` an improvement for xanthophyll concentration.
Thus, `Orangeade` is reported to contain xanthophylls at about 9-12 mg/g
of dry whole flower heads (including calyx), `Deep Orangeade` is reported
to have about 10-13 mg/g of those pigments, and `Scarletade` is said to
contain about 12-18 mg/g of xanthophyll pigments in dry flower heads
weighed with the calyx. These varieties are available from PanAmerican
Seed Co., 622 Town Road, West Chicago, Ill. 60185.
[0019] Whereas lutein is the major xanthophyll in marigold flowers, some
current varieties yield extract products with zeaxanthin ratios
[zeaxanthin/(lutein+zeaxanthin)] typically in the 3 to 5 percent range
(See Product Profile, Kemin Foods L.C., 600 E. Court Ave. Suite A, Des
Moines, Iowa 50309). As is seen from the results hereinafter, zeaxanthin
to lutein ratios obtained using `Scarletade` are typically about 4 to
about 7 percent. Thus, these known xanthophyll marigolds exhibit a
zeaxanthin ratio of about 3:100 to about 7:100.
[0020] Moehs et al., Plant Mol. Biol., 45:281-293 (2001) analyzed the
biosynthesis of carotenoids in ornamental varieties of T. erecta,
including a so-called wild type that had dark orange flowers, and plants
with yellow, pale yellow and white flowers. Among other findings, those
workers reported that although the different plants had a range in flower
color from white (mutant) to dark orange, the differences in those flower
colors were said to be due to the accumulation of very different amounts
of the same carotenoid, lutein, rather than to accumulation of different
carotenoid products or intermediates. The differences among the plants
studied appeared to relate primarily to regulation of flux through the
carotenoid pathway, rather than to the specific type of carotenoid
produced or the accumulation of biosynthetic intermediates.
[0021] In addition, the so-called wild-type and mutant (white-flowered
plant) leaves were reported to contain about the same relative quantity
of carotenoid pigments, regardless of flower color. Those pigments were
different from the pigments present in the petals. Thus, the only pigment
reported for petals was lutein, whereas the leaves were reported to
contain lutein as well as .beta.-carotene, violaxanthin and neoxanthin.
As is seen from FIG. 1, .beta.-carotene but not lutein can be a precursor
to the latter two pigments.
[0022] The Moehs et al., authors also compared the T. erecta genes they
isolated with similar carotenoid-producing genes obtained from the leaves
of Arabidopsis thaliana (Pogson et al., hereinafter). Identities between
the gene products of about 70 to about 80 percent were reported at the
protein level, with a higher level if putative plastid targeting signal
peptides were excluded, and a lower level of identity at the DNA level.
In leaves of A. thaliana, lutein is the predominant carotenoid, with
.beta.-carotene, violaxanthin and neoxanthin also being formed, but no
zeaxanthin being normally accumulated.
[0023] Carotenoid biosynthesis in T. erecta is a complex system involving
many genes and possibly two pathways. The impact of genetic mutations on
carotenoid production cannot be predicted a priori. However, classic
breeding techniques have produced `Orangeade", `Deep Orangeade` and
`Scarletade` T. erecta variants that produce the elevated levels of
xanthophylls noted above. These relatively recently bred available
varieties have not been subject to treatments that induce genetic
mutations in an attempt to increase the zeaxanthin ratios.
[0024] Several workers have examined the effects of mutagens such as gamma
irradiation, ethyl methanesulfonate (EMS) and nitrosomethylurea (NMU) on
flowering plants, including marigolds. For example, Zaharia et al.,
Buletinul Institutului Agronomic Cluj-Napoca. Seria Agricultura 44(1):
107-114 (1991) reported on the chlorophyll-deficient effects of
carotenoids in the coleoptile after seeds of Zinnia elegans, Tagetes
erecta and Callistephus chinensis were irradiated with gamma irradiation
in varying amounts. A paper by Geetha et al., Acta Botanica Indica,
20(2):312-314 (1992) reports on the chlorophyll deficient effects of
gamma irradiation on Tagetes patula.
[0025] Diaconu, Agronomie, 34(1):17-21 (1991) reported on the effects of
EMS on germinating seeds from F.sub.2 polycrosses of commonly-called pot
marigolds, or Calendula, that are not even of the genus Tagetes. Those
workers noted a wide variation in flower color, inflorescence structure,
yield and content of biologically-active substances in M.sub.2-M.sub.4
plants.
[0026] A study by Pogson et al., Plant Cell, 8:1627-1639 (1996) used EMS
to mutagenize plants of Arabidopsis thaliana. This detailed study of 4000
M.sub.2 lines reported finding two loci in the carotenoid biosynthetic
pathway in leaves that are involved with the production of lutein from
.gamma.-carotene. Those loci were referred to as lut1 and lut2. The lut2
locus was reported to be associated with the lycopene .epsilon.-ring
cyclase enzyme, whereas the lut1 locus was reported to be associated with
the lycopene .epsilon.-ring hydroxylase. Those workers noted (page 1631)
that a decrease in lutein production was compensated for by an equimolar
change in the abundance of other carotenoids, although only small amounts
of those changes were due to an increased production of zeaxanthin.
[0027] Cetl et al., Folia Fac. Sci. Nat. Univ. Purkynianae Brun Biol.,
21(1):5-56 (1980) reported extensive studies with T. erecta and other
Tagetes species that from the meager descriptions appeared to all be
ornamental varieties. Among those studies, those authors examined the
effects of various concentrations of NMU on T. erecta seeds, and examined
more than about 2000 plants. All M.sub.2 plants deviating from the
phenotype of the parental cross were recorded, and M.sub.3 plants from
M.sub.2 seeds of the phenotypically different plants were studied.
[0028] Those workers assayed plant height, plant diameter, flower head
diameter and height of the flower head, as well as time to flowering,
branching amount, branch length, cotyledon and leaf size, and flower
stalk length. No mention is made regarding flower color or carotenoid
levels in the leaves or petals.
[0029] Published PCT application WO 00/32788 of DellaPenna et al. asserts
of a method of regulating carotenoid biosynthesis in marigolds. Those
workers provide polynucleotide sequences said to be those that encode the
lycopene .beta.-ring cyclase and lycopene .beta.-ring hydroxylase needed
for the preparation of zeaxanthin from lycopene. Also disclosed is a
lycopene .epsilon.-ring cyclase useful along with the lycopene
.beta.-ring cyclase for the preparation of .alpha.-carotene from
lycopene. No teaching of the lycopene .epsilon.-ring hydroxylase needed
for lutein production is provided.
[0030] Carotenoid biosynthesis is said in PCT application WO 00/32788 to
be regulated by expression of a carotenoid synthesizing enzyme-encoding
gene already present in marigolds such as those noted above, or by use of
an anti-sense RNA encoded by such a nucleotide sequence provided. No
evidence of such regulation is provided in the application. The
phenomenon known as co-suppression by which the addition of a homologous
gene causes both the native gene and transgene not to be expressed is not
dealt with by those workers. [See for example, Fray et al., Plant Mol.
Biol., 22:589-692 (1993) or Finnegan et al., Bio/Technology, 12:883-888
(September 1994).]
[0031] U.S. Pat. No. 6,383,474 to Soudant et al. teaches that phytoene and
phytofluene, together, are effective in preventing damage caused from
oxidation and exposure to UV light. This combination is said to be useful
as a topical preparation, as a pharmaceutical or as a food additive.
[0032] .beta.-Carotene and lycopene are well-known food additives, with
lycopene consumption recently being reported to provide a reduced risk of
prostate cancer. [See, Giovannucci et al., J. Natl. Cancer Inst.,
87(23):1767-1776 (1995).] Lycopene is naturally present as the red
pigment in tomato skins, whereas .beta.-carotene is the primary
carotenoid pigment in carrots. Hauptmann et al. U.S. Pat. No. 5,618,988
teaches the preparation of carotenoid pigments such as .beta.-carotene in
storage organs of transformed plants such as carrots. Ausich et al. U.S.
Pat. No. 5,858,700 teaches the isolation of lycopene crystals from an
oleoresin as can be prepared from tomato skins. The structural formulas
of lycopene and .beta.-carotene are shown below.
[0033] An increased ratio of zeaxanthin to lutein can provide an
attractive substrate for biotechnological production of additional
xanthophylls including the red xanthophyll, astaxanthin. Astaxanthin is
widely used as a pigmenting agent for cultured fishes and shellfishes.
The complete biomedical properties of astaxanthin remain to be
elucidated, but initial results suggest that it could play an important
role in cancer and tumor prevention, as well as eliciting a positive
response from the immune system. [See Tanaka et al., Carcinogenesis
15(1):15-19 (1994); Jyonouchi et al., Nutrition and Cancer 19(3):269-280
(1993) and Jyonouchi et al., Nutrition and Cancer 16(2): 93-105 (1991).]
[0034] Astaxanthin supplied from biological sources, such as crustaceans,
yeast and green algae is limited by low yield and costly extraction
methods when compared with that obtained by organic synthetic methods.
Usual synthetic methods however, produce by-products that can be
considered unacceptable. It is therefore desirable to find a relatively
inexpensive source of (3S,3'S) astaxanthin to be used as a feed
supplement in aquaculture and as a valuable chemical for other industrial
uses.
[0035] One approach to increase the productivity of astaxanthin production
in a biological system is to use genetic engineering technology. Genes
suitable for this conversion have been reported.
[0036] For example, Misawa et al. (See U.S. Pat. No. 6,150,130) specified
DNA sequences including one isolated from the marine bacteria
Agrobacterium aurantiacus sp. nov. MK1 or Alcaligenes sp. PC-1 that
encodes a gene, referred to as crtW, used in the production of
astaxanthin from zeaxanthin as a substrate by way of 4-ketozeaxanthin.
Kajiwara et al. (See U.S. Pat. No. 5,910,433) identified a polynucleotide
molecule, referred to as bkt, isolated from Haematococcus pluvialis that
encodes a polypeptide having a beta-C-4-oxygenase activity for the
production of (3S,3'S)astaxanthin from a host microorganism or a plant.
In addition, Hirschberg et al. (See U.S. Pat. No. 5,965,795) described
another DNA gene sequence from Haematococcus pluvialis, referred to as
crtO, that encodes an enzyme that synthesizes astaxanthin from zeaxanthin
by way of 4-ketozeaxanthin. Still further, Cunningham (See WO 99/61652)
reported isolation of a DNA that encodes a protein having ketolase enzyme
activity from Adonis aestivalis, a plant species having deep red flower
color due in part to the accumulation of the ketocarotenoid astaxanthin.
[0037] It would therefore be useful if a marigold plant could be provided
whose flower petals or leaves or both contain a commercially useful
amount of xanthophylls and an altered ratio of lutein and zeaxanthin such
that the usually reported 4 to about 7 percent zeaxanthin level were
raised and the amount of lutein were decreased. It would also be useful
if the ratios of other pigments could also be raised, and if such a plant
had substantially the same phenotypical characteristics as a usual
marigold plant grown adjacent to it. It would be further useful if a
marigold could be produced that accumulated .beta.-carotene or lycopene
or both in the flower petals or leaves or both. The present invention
provides several marigold plants, flower petals, leaves, seed that
produces them, hybrids, oleoresins, mixtures of zeaxanthin and lutein,
lycopene and .beta.-carotene in proportions not normally found in
marigolds, as well as comestible materials containing zeaxanthin, lutein,
.alpha.-cryptoxanthin, antheraxanthin, neoxanthin and violaxanthin,
lycopene, phytoene and .beta.-carotene dissolved or dispersed in a
comestible medium.
BRIEF SUMMARY OF THE INVENTION
[0038] The present invention contemplates marigold plants whose petals,
leaves or both flower petals and leaves contain one or more of an
enhanced zeaxanthin ratio, an enhanced neoxanthin plus violaxanthin
ratio, an enhanced .beta.-carotene ratio, an enhanced lycopene ratio, an
enhanced .alpha.-cryptoxanthin ratio, an enhanced phytoene ratio or an
enhanced phytofluene ratio compared to such a ratio present in a
non-mutant marigold. In addition, the flower petals often contain a
measurable amount of zeta-carotene (.zeta.-carotene), whereas that
compound is not measurable; i.e., is present at less than 0.1 or 0.2
percent, in the petals of a non-mutant marigold plant.
[0039] A stated ratio is determined as a percentage of the first-named
pigment divided by the sum of the percentages of that pigment and lutein
as determined after saponification by chromatographic techniques
discussed hereinafter. Thus, the zeaxanthin ratio is illustratively
defined herein as [zeaxanthin %/(zeaxanthin %+lutein %)].
[0040] Preferably the petals, leaves or both the petals and leaves of such
a plant at least exhibit a zeaxanthin ratio greater than about 1:10,
preferably greater than about 2:10, up to about 1.0. That ratio can be up
to one because lutein cannot be detected in some leaves and is present in
a very small amount relative to another pigment such as zeaxanthin in
petals. In some embodiments, the flower from which the petals are taken
has a carotenoid content of about 4 to about 25 mg/g dry weight, whereas
in other plants the petal carotenoid content can be lower. The carotenoid
content of leaves is typically about 0.5 to about 1.25 mg/g dry weight.
The flower petals and leaves are typically present in comminuted form.
[0041] Another aspect of the invention contemplates a marigold plant, or a
regenerable portion thereof, whose flower petals or leaves or both
contain one or more of an enhanced zeaxanthin ratio, an enhanced
neoxanthin plus violaxanthin ratio, an enhanced .beta.-carotene ratio, an
enhanced lycopene ratio, an enhanced .alpha.-cryptoxanthin ratio, an
enhanced phytoene ratio or an enhanced phytofluene ratio and preferably
at least a zeaxanthin ratio that is greater than about 1:10, preferably
greater than about 2:10, and up to about 1.0. The petals of a
contemplated plant typically contain a measurable amount of
zeta-carotene, as discussed before.
[0042] Some contemplated plants have flower petals that contain little if
any xanthophylls and rather contain a total of about 50 percent or more
.beta.-carotene and lycopene isomers. The flower petals of these plants
are orange to red from carotenoid pigments which colors are not normally
found in marigolds. Marigolds can exhibit some red coloration due to cell
sap-soluble anthocyanin pigments.
[0043] The plant that produced the desired petals and leaves is a mutant
whose phenotype except as to carotenoids can be substantially the same as
that of an adjacently-grown non-mutant plant, or that phenotype can be
different. In one aspect, a contemplated marigold plant is an inbred or
hybrid between another contemplated mutant plant and a non-mutant in
which the non-mutant plant is a hybrid neither of whose parents are
mutants. In another aspect, the contemplated marigold plant is a cross
(hybrid) of two mutant parents.
[0044] A contemplated plant in one embodiment is typically a hybrid one of
whose parents resulted from the mutation or later generation hybrid. A
contemplated marigold plant of one aspect contains an amount of
carotenoids, measured as the saponified pigments extractable from the
flowers, that is about 4 to about 25 grams per kilogram of dry flowers or
about 4 to about 25 mg/g dry weight. A contemplated marigold of another
aspect contains a lesser carotenoid content. The pollen and an ovule of
such a plant are separately contemplated. The regenerable portion of such
a contemplated plant comprises cells that include embryos, meristems,
pollen, leaves, anthers, roots, root tips, and flowers, or protoplasts or
callus derived therefrom.
[0045] Another embodiment contemplates a seed that on planting in a
suitable environment and growth to maturity yields a marigold plant whose
flower petals or leaves or both contain one or more of an enhanced
zeaxanthin ratio, an enhanced neoxanthin plus violaxanthin ratio, an
enhanced .beta.-carotene ratio, an enhanced lycopene ratio, an enhanced
.alpha.-cryptoxanthin ratio, an enhanced phytoene ratio or an enhanced
phytofluene ratio. Preferably, an above-noted ratio is greater than at
least about 1:10, more preferably greater than about 2:10, and up to
about 1.0. The petals of a contemplated plant again typically contain a
measurable amount of zeta-carotene, typically at least 1 percent or more,
as discussed before.
[0046] A mutant marigold plant oleoresin having one or more of an enhanced
zeaxanthin ratio, an enhanced neoxanthin plus violaxanthin ratio, an
enhanced .beta.-carotene ratio, an enhanced lycopene ratio, an enhanced
.alpha.-cryptoxanthin ratio, an enhanced phytoene ratio or an enhanced
phytofluene ratio relative to an oleoresin from a non-mutant marigold.
Again, a noted ratio is preferably at least greater than about 1:10, more
preferably greater than about 2:10, and up to about 1.0. A contemplated
oleoresin also usually contains a measurable amount of zeta-carotene, as
discussed before.
[0047] A food additive comprised of substantially whole or partial
marigold petals in dry or native form is also contemplated. Such
contemplated petals can be from any of the plants discussed herein, all
of which exhibit one or more of an enhanced zeaxanthin ratio, an enhanced
neoxanthin plus violaxanthin ratio, an enhanced .beta.-carotene ratio, an
enhanced lycopene ratio, an enhanced .alpha.-cryptoxanthin ratio, an
enhanced phytoene ratio or an enhanced phytofluene ratio relative to a
petal from a non-mutant marigold. One group of such petals contains
zeaxanthin esters and is substantially free of both neoxanthin and
violaxanthin, with zeaxanthin constituting at least about one-half of the
extractable carotenoids and being measured as the dialcohol after
saponification.
[0048] A composition suitable for use as a food or feed supplement
containing one or more marigold-derived carotenoid pigments is also
contemplated. The food or feed supplement comprises a mixture of
zeaxanthin and lutein fatty acid esters dissolved or dispersed in a
comestible medium, wherein the zeaxanthin ratio is greater than about
1:10, preferably greater than about 2:10, and up to about 1.0. Another
composition suitable for use as a food or feed supplement comprises
zeaxanthin and lutein dissolved or dispersed in a comestible medium,
wherein the zeaxanthin ratio is greater than about 1:10, preferably
greater than about 2:10, and up to about 1.0. A further composition
suitable for food use contains phytoene, lycopene or .beta.-carotene
dissolved or dispersed in a comestible medium, wherein the phytoene,
lycopene or .beta.-carotene ratio is greater than about 1:10, preferably
greater than about 2:10, and up to about 1.0.
[0049] Yet another aspect of the invention contemplates a marigold plant,
or a regenerable portion thereof, whose flower petals contain zeaxanthin
esters and are substantially free of both neoxanthin and violaxanthin,
wherein zeaxanthin constitutes at least about one-half of the extractable
carotenoids and is measured as the dialcohol after saponification.
Another embodiment contemplates a seed that on planting in a suitable
environment and growth to maturity yields an above-described marigold
plant. A marigold oleoresin whose carotenoids include zeaxanthin esters
and are substantially free of both neoxanthin and violaxanthin esters is
also contemplated. A carotenoid composition suitable for use as a food or
feed supplement that contains at least about one-half zeaxanthin and more
than ten percent of one or more other carotenoids but is substantially
free of both neoxanthin and violaxanthin is further contemplated.
BRIEF DESCRIPTION OF THE DRAWING
[0050] In the drawing forming a part of this disclosure,
[0051] FIG. 1 is a schematic representation of the biological synthesis
pathway for the production of lutein and zeaxanthin in plants in which
phytoene, the first C.sub.40 carotenoid in the pathway, is converted in
several steps (four arrows) through zeta-carotene (.zeta.-carotene) to
lycopene, after which the pathway splits to form .delta.-carotene that
contains one .epsilon.-ring, then .alpha.-carotene that contains one
.epsilon.-ring and one .beta.-ring or to form .beta.-carotene that
contains one .beta.-ring, then .beta.-carotene that contains two
.beta.-rings, and after several steps, to lutein or zeaxanthin,
respectively, and the zeaxanthin branch continuing to the
epoxide-containing xanthophylls antheraxanthin, violaxanthin and
neoxanthin.
[0052] As used herein, the term "zeaxanthin ratio" is defined as the
quantity of zeaxanthin present in a dried flower petal or leaf divided by
the quantity of zeaxanthin plus lutein [zeaxanthin/(lutein+zeaxanthin)]
present in that petal or leaf. The "neoxanthin plus violaxanthin ratio"
is similarly calculated as the ratio of neoxanthin+violaxanthin divided
by the sum of those two pigments plus lutein. The ".beta.-carotene
ratio", the "lycopene ratio", the ".alpha.-cryptoxanthin ratio", the
"phytoene ratio" and the "phytofluene ratio" are similarly calculated
using the named pigment amount as the sum of its isomers as the numerator
and the sum of that pigment plus lutein as the denominator. Those sums
can also be as percentages. The pigment quantities are determined by high
performance liquid chromatography (HPLC) after saponification of a dried
flower petal or leaf extract as discussed hereinafter so that the amount
of each of lutein and zeaxanthin (or other pigment) is measured in the
free compound form, e.g., alcohol form for lutein and zeaxanthin, present
after saponification rather than in the esterified form that is present
in the fresh flower petal, and chlorophyll that may be present in a leaf
extract is destroyed. Some of the flower petals and leaves of plants
discussed herein contain very low or unmeasurable amounts of lutein or
lutein esters, e.g., less than about 0.1-0.2 percent. When that is the
case, the amount of lutein in the denominator of a ratio approaches zero
and the ratio approaches one.
[0053] The word "oleoresin" is used herein to mean an extract of plant
tissues that contains plant pigments such as the xanthophylls discussed
herein in their esterified forms, sometimes accompanied by amounts of
other plant products and pigments such as other carotenoids such as
.beta.-carotene, as well as small amounts of solvent such as hexane or
acetone, typically less than 1 percent organic solvent. Xanthophylls are
typically present as mono- or diesters in flower-petals and are typically
present as free alcohols in marigold leaves. Carotenes such as
.beta.-carotene or lycopene are present as free, non-chemically-combined
compounds. Chlorophyll is present in marigold leaves and largely absent
in the petals. Thus, an oleoresin prepared from flower petals contains
xanthophyll esters and/or hydrocarbon carotenes and is largely free of
chlorophyll, whereas an oleoresin prepared from marigold leaves contains
chlorophyll and free xanthophylls and carotenes. Both chlorophyll and
xanthophyll esters are decomposed by saponification of the oleoresin. A
contemplated oleoresin is a solid or semi-solid material.
DETAILED DESCRIPTION OF THE INVENTION
[0054] The present invention contemplates marigold plants, seeds, flower
petals, leaves and materials that can be prepared therefrom. A
contemplated plant additionally has flower petals, leaves or both that
contain an enhanced ratio of one or more carotenoids as compared to
previously known marigold plants. The petals and/or leaves of a
contemplated plant thus contain one or more of an enhanced zeaxanthin
ratio, an enhanced neoxanthin plus violaxanthin ratio, an enhanced
.beta.-carotene ratio, an enhanced lycopene ratio, an enhanced
.alpha.-cryptoxanthin ratio, an enhanced phytoene ratio or an enhanced
phytofluene ratio. The leaves or petals of a contemplated plant can be
free of lutein; i.e., the leaves or petals contain lutein at less than
about 0.1 to about 0.2 percent of the extractable, saponified
carotenoids. These contemplated marigold plants are T. erecta, as
compared to T. patula or T. tenuifolia, or other Tagetes species. In
addition, a contemplated plant can be a xanthophyll marigold, as such
plants have been described before and are understood by workers of skill
in this art.
[0055] The usual ratio of zeaxanthin to zeaxanthin+lutein in marigold
petals is on the order of about 1:15 to about 1:25, so that when only
zeaxanthin and lutein amounts are used for calculations, zeaxanthin is
about 5 to about 7 percent of the amount of lutein plus zeaxanthin. An
article by Quackenbush et al., J. Assoc. Off. Agri. Chem., 55:617-621
(1972) reported a zeaxanthin to lutein ratio in one group of American
yellow T. erecta marigold flower petals that was unusually high at about
1:4.4, whereas the total concentration of xanthophylls in those petals
was unusually low at about 0.4 mg/g dry weight. A Mexican variety was
said by those authors to contain 11.1 percent zeaxanthin when lyophilized
petals were assayed and 3.8 percent when fresh petals were assayed. The
higher value is not in keeping with the remainder of the data and is
believed to be incorrect. The preferred zeaxanthin ratio in petals
contemplated here is even larger, being greater than about 1:10 and
preferably greater than about 2:10, on up to about 1.0, as will be
discussed hereinbelow, and the amount of petal carotenoids is preferably
at least about 4 mg/g dry weight.
[0056] A contemplated marigold plant has flower petals that contain a
zeaxanthin ratio greater than about 1:10 and preferably greater than
about 2:10. More preferably still, a contemplated marigold plant has
flower petals that contain a zeaxanthin ratio greater than about 3:10.
Most preferably, that ratio is greater than 5:10, and can be about 1.0.
The flower from which the petals are taken has a carotenoid content of
about 4 to about 25 mg/g dry weight, and preferably about 10 to about 20
mg/g dry weight. Such a marigold plant also preferably has leaves that
contain a zeaxanthin ratio greater than about 1:10 and preferably greater
than about 2:10. More preferably still, a contemplated marigold plant has
leaves that contain a zeaxanthin ratio greater than about 3:10. Most
preferably, that ratio is greater than 5:10, and can be about 1.0. The
contemplated leaves have a carotenoid content of about 0.2 to about 1.25
mg/g dry weight, and preferably about 0.5 to about 1 mg/g dry weight.
[0057] In some embodiments, the lutein concentration of the petals of a
contemplated plant is about 80 to about 90 percent of the lutein present
in a parental, non-mutant plant. In other embodiments, the amount of
lutein is less than about 75 percent of that present in a non-mutant
plant. In still further embodiments, the amount of lutein present in the
flower petals is less than about 15 percent of that present in the petals
of a non-mutant marigold plant. Indeed, lutein can be substantially
absent from the leaves or petals of particularly preferred plants; i.e.,
present at less than about 0.2 percent of the carotenoids.
[0058] A contemplated marigold can also exhibit differences in ratios of
one or more other pigments relative to lutein. Thus, the neoxanthin plus
violaxanthin ratio in a parental plant can be about 0.01 to about 0.02
for a non-mutant petal extract and about 0.17 to about 0.33 in leaves.
That ratio in contemplated mutant plant petals and leaves of one
preferred embodiment is about 1:5 (0.2) to about 1:1 (one). In some
Tables hereinafter, neoxanthin and violaxanthin are measured together as
they were difficult to separate chromatographically.
[0059] The .beta.-carotene ratio in non-mutant plants is typically about
less than 0.007 for flower petals and about 0.25 to about 0.3 for leaves.
In a contemplated mutant marigold, that ratio is about 1:10 and
preferably greater than about 2:10 in petals. More preferably still, a
contemplated marigold plant has flower petals that contain a
.beta.-carotene ratio greater than about 3:10. Most preferably, that
ratio is greater than 5:10, and can be about 1.0. The ratio for mutant
marigold leaves is about 0.4 to one.
[0060] Lycopene is normally not found in either marigold leaves or flower
petals. The lycopene isomer ratio is typically, therefore zero for a
usual, non-mutagenized marigold. A contemplated mutant plant can exhibit
a lycopene ratio of about 1:10 and preferably greater than about 2:10 in
petals. More preferably still, a contemplated marigold plant has flower
petals that contain a lycopene ratio greater than about 3:10. Most
preferably and more usually because of the usual absence of lycopene from
marigold flower petals, that ratio is greater than 5:10, and is about
1.0.
[0061] .alpha.-cryptoxanthin typically constitutes less than one percent
of colored carotenoids of non-mutant plant petals and the
.alpha.-cryptoxanthin ratio is consequently about 0.01 in non-mutant
flower petals. The .alpha.-cryptoxanthin ratio is about 0.25 to about
0.9, and is most preferably and usually about one in the petals of
preferred mutated plants.
[0062] Phytoene can be present in petals at about 3 to about 0.3 percent
of the carotenoids in non-mutant plants and can be present at about 35
percent in some mutant flower petals that typically contain a reduced
amount of lutein. Exemplary phytoene ratios can be from about 0.3 to
about 1 in a contemplated plant as compared to phytoene ratios of about
0.003 to about 0.03 in non-mutant plants. Phytoene concentrations are
largely unchanged in leaves of mutant plants as compared to non-mutant
plant leaves.
[0063] Phytofluene amounts in non-mutant plant petals are typically about
the same as those observed for phytoene, whereas the amount present in
the petals of a contemplated mutant plant is generally about 40 to about
70 percent of the phytoene amount. The phytofluene ratio for a non-mutant
plant is usually about 0.005 to about 0.03, whereas that ratio for a
contemplated mutant plant is about 0.2 to about 1. Phytofluene has not
been observed in leaf extracts.
[0064] The enhancements observed in the above ratios are typically at
least about two-fold. In particular embodiments, a ratio can be enhanced
by about ten- to about one hundred-fold. Regardless of the percentage of
enhancement, the ratio of each of the above carotenoids to each
carotenoid plus lutein is 1:10 or greater, and preferably about 2:10 or
greater.
[0065] The petals or leaves or both of a particular plant can have one or
more of the above-recited enhanced ratios. In usual practice, two or more
of the before-described enhanced ratios are present. Thus, for example,
the zeaxanthin ratio and the .beta.-carotene ratio can be enhanced, the
lycopene ratio and the .beta.-carotene ratio can be enhanced, or the
zeaxanthin ratio and the neoxanthin plus violaxanthin ratio can be
enhanced. Similarly, three or more of the ratios can be elevated.
[0066] .alpha.-Cryptoxanthin is a particularly interesting compound in
that it has been found to be present in relatively high levels in a
number of mutants and is not otherwise readily available. Thus,
.alpha.-cryptoxanthin was present at about 20 to about 40 percent of
colored carotenoids in some mutants. The .alpha.-cryptoxanthin ratio of
such plants was consequently greatly enhanced as compared to those plants
whose petals contained more usual carotenoid profile.
[0067] The petals of a contemplated plant typically contain a measurable
amount of zeta-carotene (.zeta.-carotene), whereas that pigment is not
present in a measurable amount; i.e., present at less than 0.2 percent,
in the petals of a non-mutant marigold plant. Typically, zeta-carotene is
present in an amount of at least about 1 percent of the petal
carotenoids. That amount of zeta-carotene can be in the range of about 3
to about 7 percent in some embodiments, and at about 20 percent in other
embodiments.
[0068] Measurable amounts of a pigment depend upon the pigment, the
separation system used, the chromatographic column used, eluting solvent,
as well as a number of other variables well known to skilled workers. For
purposes of this disclosure, a pigment is considered absent if its
presence is at less than about 0.1-0.2 percent.
[0069] Another aspect of the present invention contemplates a marigold
plant whose leaves and/or flower petals are substantially free of lutein
(i.e., contain lutein at less than about 5 percent by weight of the total
weight of carotenoids present), and at least about one-half of whose
carotenoids are comprised of zeaxanthin and .beta.-carotene. Thus,
together, zeaxanthin plus .beta.-carotene together constitute at least
about one-half of the total carotenoids. More preferably, zeaxanthin and
.beta.-carotene together constitute about 60 to about 95 weight percent
of the carotenoid pigments present in leaves and/or petals of a
contemplated plant.
[0070] Marigold petals can be used for extraction of their carotenoids and
carotenoid esters as well as by themselves as food additives. A
contemplated food additive is comprised of whole or partial marigold
petals in dry or native (hydrated form as plucked from a flower head)
form. The petals so used can be sprinkled on foods such as salads and
desserts as a decorative garnish as well as for the benefits obtained
from ingesting the carotenoids. Substantially whole petals; i.e., in the
form in which the petals are plucked from the flower head, in native
form, are preferred for decorative purposes, whereas partial petals such
as finely comminuted, dried petals are typically used for additions to
cooked foods or for additives to animal feeds.
[0071] Such contemplated petals can be from any of the plants discussed
herein, all of which exhibit one or more of an enhanced zeaxanthin ratio,
an enhanced neoxanthin plus violaxanthin ratio, an enhanced
.beta.-carotene ratio, an enhanced lycopene ratio, an enhanced
.alpha.-cryptoxanthin ratio, an enhanced phytoene ratio or an enhanced
phytofluene ratio relative to a petal from a non-mutant marigold. One
group of such petals contains zeaxanthin esters and is substantially free
of both neoxanthin and violaxanthin, with zeaxanthin constituting at
least about one-half of the extractable carotenoids and being measured as
the dialcohol after saponification.
[0072] Another preferred use of marigold petals is as a food additive
comprised of dried, finely comminuted marigold petals. This marigold food
product can be referred to as a marigold meal, and can be sprinkled or
shaken on or into a food product much as are red pepper flakes or ground
oregano leaves.
[0073] Such a marigold meal can be prepared from known marigolds such that
the petals contain lutein and zeaxanthin as the principal xanthophylls as
measured as the dialcohols after saponification, and wherein the
zeaxanthin ratio is about 3 to about 7:100. More preferably, the petals
contain one or more of an enhanced zeaxanthin ratio, an enhanced
neoxanthin plus violaxanthin ratio, an enhanced .beta.-carotene ratio, an
enhanced lycopene ratio, an enhanced .alpha.-cryptoxanthin ratio, an
enhanced phytoene ratio or an enhanced phytofluene ratio. Each of those
enhanced ratios is about 1:10 or more, and preferably about 2:10 or
greater, as discussed before.
[0074] In some embodiments, the petals contain zeaxanthin esters and are
substantially free of both neoxanthin and violaxanthin, with zeaxanthin
constituting at least about one-half of the extractable carotenoids when
measured as the dialcohol after saponification. In other embodiments,
petals contain an enhanced lycopene ratio relative to dried, comminuted
petals from a non-mutant marigold. In still other embodiments,
.alpha.-cryptoxanthin is the most abundant carotenoid present in the
dried, comminuted flower petals.
[0075] In some these embodiments, the lutein present in leaves and/or
petals is less than about 3 weight percent and more preferably less than
about one weight percent of the extractable carotenoids. The
.beta.-carotene present in these petals and/or leaves can be present at
about 5 to about 80 percent of the carotenoids.
[0076] A further aspect of the invention contemplates a marigold plant, or
a regenerable portion thereof, whose flower petals contain zeaxanthin and
are substantially free of both neoxanthin and violaxanthin, wherein
zeaxanthin constitutes at least about one-half of the extractable
carotenoids and is measured as the dialcohol after saponification. Thus,
the zeaxanthin present is typically present as a mono- or diester as
noted elsewhere, but is measured as the free diol after saponification of
a petal extract. Surprisingly, a plant contemplated here has flower
petals that are substantially free of both neoxanthin and violaxanthin.
[0077] As is seen from the data in Tables 6a-6c, exemplary petals of prior
art plants and several mutant plants prepared herein have enhanced
rations of zeaxanthin to zeaxanthin plus lutein and readily measurable
amounts of neoxanthin and violaxanthin. On the other hand, the data for
the plants of Tables 8a-8c illustrate several plants wherein zeaxanthin
constitutes one-half or more of the extractable carotenoids and
neoxanthin and violaxanthin amounts are less than a measurable amount
using the procedures discussed hereinafter, so that the flowers of such
plants are substantially free of those two carotenoids.
[0078] Another embodiment contemplates a seed that on planting in a
suitable environment and growth to maturity yields a marigold plant as
described immediately above.
[0079] A marigold oleoresin whose carotenoids include zeaxanthin esters
and are substantially free of both neoxanthin and violaxanthin esters is
also contemplated. A carotenoid composition suitable for use as a food or
feed supplement that contains at least about one-half zeaxanthin and more
than ten percent of one or more other carotenoids but is substantially
free of both neoxanthin and violaxanthin is further contemplated.
[0080] As already noted, xanthophylls such as lutein and zeaxanthin are
present in flower petals primarily as mono- or diesters of fatty acids
such as lauric, myristic, palmitic, stearic, oleic or the like, rather
than as free diol compounds. As such, when a zeaxanthin or other
xanthophyll ratio is discussed herein, that ratio is determined by
extracting one or more flower petals with hexane or other appropriate
solvent to obtain a composition such as an oleoresin comprised of
esterified xanthophylls. That composition is then saponified using a base
such as potassium hydroxide to cleave the esters and form free carotenoid
dialcohols. The free carotenoid xanthophyll alcohols are thereafter
separated from the saponification reaction mixture and separated as
desired using high performance liquid chromatography (HPLC). The ratios
of materials present are determined by the areas under the appropriate
HPLC peaks using standard methods of integration.
[0081] It is to be noted that Table 10, hereinafter, illustrates that some
contemplated plants exhibit free xanthophylls in their petals rather than
the usually found xanthophyll esters. As such, free
xanthophyll-containing edible foods and feed supplements can be prepared
that do not require saponification.
[0082] The analytical method utilized herein to determine the pigment
ratios is exemplified hereinafter, and provides similar results to those
published by others, with different specific techniques being used by
different laboratories largely for reasons of convenience. Using the
procedure preferred here, flowers approximately 98 percent fully opened
are selected for analysis. Petals are removed about one-third of the
distance from the flower center from the selected flowers.
[0083] Leaves can be harvested and extracted at substantially any time.
Xanthophylls are typically present as free compounds in leaves as are
carotenes. Chlorophyll present in leaves is also extracted with the
carotenoid pigments so assays are carried out after saponification of the
extract as that treatment destroys chlorophyll. Leaves are assayed for
carotenoid content as are the petals.
[0084] A standard analytical method used in the industry for determining
carotenoid levels in
plant extracts is that of the AOAC 1984, Official
Methods of Analysis (14.sup.th ed), the Association of Official
Analytical Chemists, Arlington, Va., USA, the results of whose assays are
similar to those obtained herein.
[0085] A contemplated marigold plant is a mutant of a parental line. That
is, a first line or cross or seed is treated with a mutagen (mutagenized)
to provide a mutagenized plant that is typically self-pollinated (selfed)
one or more times. A plant contemplated herein can arise from the
mutagenesis itself, from one of the selfings or from a cross of a
mutagenized plant or offspring with another mutagenized or
non-mutagenized plant.
[0086] Substantially any kind of mutagen can be used to produce a
contemplated plant, and exemplary mutagens are discussed hereinafter.
Although some contemplated mutant marigolds have a phenotype that is
substantially different from that of adjacently-grown non-mutant marigold
parental plant, other contemplated mutants exhibit substantially the same
phenotype as that of an adjacently-grown non-mutant parental plant,
except for phenotypic traits related to carotenoids. More specifically
for the latter plants, when one compares plant properties such as plant
height, plant diameter, flower head diameter, flower head height, time to
flowering, branching amount, length of branches, flower stalk length,
hypocotyl length, cotyledon length and cotyledon width between a parent
and a mutant plant, the values of those properties for some contemplated
mutant plants are each within about 90 percent of those of the parental
plant, including the standard deviations in the measurements. More
preferably, the values for those properties of the mutant are within
about 95 percent of the parent, and most preferably, the values are the
same, within the standard deviation. On the other hand, other mutant
plants differ greatly in one or more phenotypic traits.
[0087] A carotenoid-related phenotypic difference between the parental and
mutant plants is the quantity of xanthophyll or carotene pigment that can
be obtained from the flowers of the mutant. Parental plants such as
`Scarletade` or `Deep Orangeade` typically have about 10 to about 18 mg/g
dry whole flower head weight of extractable xanthophyll pigments and
contain very little carotenes. A contemplated mutant plant having a high
zeaxanthin ratio preferably contains about the same amount of carotenoid
in the flower petals, but can contain as little as about 4 mg/g dry
weight, particularly where the ratio of zeaxanthin to lutein is very high
such as about 9:1 or greater. Other mutants can contain little
xanthophylls and a relatively large amount of one or more carotenes.
[0088] The leaves of a contemplated marigold can also exhibit a phenotypic
difference between the parental and mutant plants in one or more of
several respects, including the carotenoid content as well as one or more
of the before-discussed carotenoid ratios present in the leaves as
measured in a saponified oleoresin. The previously noted paper of Moehs
et al., Plant Mol. Biol., 45:281-293 (2001) reported that leaf carotenoid
ratios and contents were constant, whereas carotenoid concentration in
the petals differed. Here, it is found that one or more of the
before-mentioned zeaxanthin ratio, antheraxanthin ratio, neoxanthin plus
violaxanthin ratio, phytoene ratio, phytofluene ratio, .beta.-carotene
ratio, lycopene ratio and .alpha.-cryptoxanthin ratio in mutant plants
differed considerably from parental non-mutant plants. In addition, the
petals of the mutant plants examined typically exhibited a measurable
amount of zeta-carotene, whereas no measurable amount zeta-carotene was
observed to be present in the parental non-mutant plants.
[0089] Phenotypic comparisons are made between adjacently-grown plants. As
used herein, the term "adjacently-grown" is used to mean plants grown
under as similar conditions of light, heat, growth medium, humidity and
nutrients as can be achieved so that growth conditions do not govern the
phenotype. For greenhouse-grown plants, "adjacently-grown" means plants
grown under conditions as similar as possible on the same bench. For
field-grown plants, "adjacently-grown" means plants grown under
conditions as similar as possible in the same or adjoining fields.
[0090] Mutagenic agents useful for altering plants are well known in the
art, as are methods of using such agents. Exemplary chemical mutagens
include nitrosomethylurea (NMU), ethyl methanesulfonate (EMS), methyl
methanesulfonate, diethyl sulfate, nitrosoguanidine, and ethylnitrosourea
of which EMS is preferred herein. NMU can be used as discussed in Cetl et
al., Folia Fac. Sci. Nat. Univ. Purkynianae Brun. Biol., 21(1): 5-56
(1980), whereas EMS is typically utilized at about 0.25 to about 1
percent by volume (v/v), and preferably at about 0.2 to about 0.8
percent. Gamma irradiation is also a useful mutagenic agent when used to
irradiate seeds at a dose of 200 to about 20,000 rads (0.2 to about 20
krads).
[0091] In addition to chemical mutants, plants can also be mutated using
ionizing radiation as by gamma rays or neutrons and also by recombinant
DNA techniques. As is illustrated hereinafter, ionizing radiation and
recombinant DNA techniques such as gene silencing can also be used to
effect alterations in carotenoid profiles. These plants can be thus
referred to as chemically-induced, ionizing radiation-induced and
recombinantly-induced mutants, respectively. As a consequence, a mutant
marigold is defined herein as a marigold plant obtained by
chemically-induced mutation, ionizing radiation-induced mutation or
recombinantly-induced mutation.
[0092] Thus, gamma rays and fast neutron bombardment have been used for
other plants to cause deletions of one or more genes. Gene silencing can
be effected by over expression of a sense strand of a gene that leads to
down-regulation via a mechanism referred to as co-suppression. Down
regulation can also be achieved by expression of antisense genes for one
or more enzymes present in a carotenoid-production pathway. Still further
techniques are well known to workers skilled in this art.
[0093] Regardless of the mutagen used, the phenotype of the resulting
mutant plant, including carotenoid-related traits such as the zeaxanthin
ratio and the amount of xanthophylls in the petals, is usually
substantially identical to that of the parent, so that a very large
percentage of the mutants obtained are not useful. In addition, plants
seeming to have the same phenotype as the parent need to be screened to
locate a desired mutant plant. Those screenings, although tedious, are
routinely carried out and involve analysis of carotenoid pigments from
one or more single flower petals or leaves or both. Thus, the preparation
of a desired mutant is a relatively rare, but repeatable event. For
example, in one study herein, twenty-three useful mutants were obtained
from almost 22,000 mutant plants examined. In another study, about
twenty-four useful mutants out of about 8,200 examined plants were
obtained.
[0094] As already noted, a contemplated plant can be a plant that grows
from the mutagenized seed or can be a selfing or cross. In one preferred
embodiment, a contemplated marigold is a hybrid formed by crossing the
flowers of two plants that arose from two different mutagenized plants
from independent M.sub.1 plants (M.sub.2.times.M.sub.2). In another
embodiment, a contemplated marigold is a hybrid formed by crossing the
flowers of one plant that arose from one mutagenized plant with a
non-mutagenized plant. In still another embodiment, a contemplated plant
is a hybrid formed by back-crossing a hybrid with one or the other of its
immediate parental flowers. The product of the crossing of two different
hybrid plants is contemplated as is the product of the selfing of a
hybrid.
[0095] As has already been mentioned, a contemplated marigold plant can
itself be an immediate product of a mutation event, such as a product of
the seed produced after the mutation process. That plant can also be a
product of one or more crosses of one mutant with another or of mutant
selfings. A contemplated plant can also be the result of a cross between
mutant and non-mutant parental plants. The produced plants are screened
and selected for desired carotenoid characteristics.
[0096] The present invention also contemplates the pollen and an ovule of
a contemplated plant. The regenerable portion of a contemplated plant is
also itself contemplated and includes cells selected from the group
consisting of embryos, meristems, pollen, leaves, anthers, roots, root
tips, and flowers, or protoplasts or callus derived therefrom. Methods
for regenerating plants from cells are well known to those skilled in the
art, and dicotyledonous plants such as marigolds are particularly
amenable to such regeneration.
[0097] A marigold oleoresin comprised of fatty acid esters of lutein and
zeaxanthin in which the zeaxanthin ratio is greater than about 1:10 and
preferably greater than about 2:10 is also contemplated. More preferably,
that ratio is greater than about 3:10 and is most preferably about 1.0. A
contemplated marigold oleoresin contains a zeaxanthin ratio as is present
in the petals or leaves of a contemplated marigold as discussed before.
Oleoresins are items of commerce and are sold to processors for further
treatment in the production of human or other animal food or feed
supplements. A contemplated oleoresin also typically contains a
measurable amount of zeta-carotene.
[0098] In an illustrative marigold oleoresin preparation, xanthophyll
esters; i.e., zeaxanthin or mixture of zeaxanthin and lutein esters and
possibly other xanthophyll esters and carotenes such as zeta-carotene,
are extracted from dried marigold flowers with hexane, acetone, ethyl
acetate, toluene, tetrahydrofuran (THF) and the like organic solvent, or
a mixture thereof. The extraction is carried out according to procedures
known in the art. The solvent(s) is removed, resulting in an extract that
typically contains a high level of the xanthophyll esters and is about 99
percent and preferably about 99.9 percent free of the extracting organic
solvent; i.e., contains less than about 1 percent and preferably less
than about 0.1 percent organic solvent by weight. The resulting
solvent-free extract is referred to as a marigold oleoresin. A leaf
extract is similarly prepared, and contains free xanthophylls, carotenes
and chlorophyll.
[0099] A composition suitable for use as a food or feed supplement for
human or other animals such as poultry like chickens and turkeys, fish
like trout and salmon and crustaceans like shrimp, lobsters and crabs is
also contemplated. A contemplated food or feed supplement can be used to
provide color to the skin and fat of those animals as well as to the egg
yolks of such animals, and particularly chickens.
[0100] One food or feed supplement comprises a mixture of fatty acid
esters of zeaxanthin alone or zeaxanthin, lutein and other carotenoids as
are present in a marigold oleoresin. That mixture of marigold-derived
mostly fatty acid esters is dissolved or dispersed in a comestible
medium, wherein the zeaxanthin and lutein fatty acid esters are present
at a zeaxanthin ratio that is greater than about 1:10, preferably greater
than about 2:10, more preferably greater than about 3:10, and up to about
1.0. This food or feed supplement can thus be prepared by suitable
purification of a before-described oleoresin as by dissolution and
filtration, followed by dissolution or dispersion of the purified mixed
esters in an appropriate comestible medium.
[0101] An oleoresin and food product can be similarly prepared from
marigold petals, leaves or both using plants that exhibit enhanced levels
of the other pigments noted herein such as phytoene, .beta.-carotene and
lycopene, for example. Where the desired marigold-derived pigment(s) is a
carotene, rather than a xanthophyll, saponification is typically not
needed to hydrolyze an ester as no esters are present. However, as noted
in U.S. Pat. No. 5,858,700, a saponification reaction can be used to free
a pigment such as lycopene from the surrounding plant materials.
[0102] In some embodiments, the comestible medium is an edible
triglyceride oil, whereas in other embodiments the comestible medium is a
binding agent such as is frequently found in pharmaceutical products such
as pills and tablets (a pharmaceutically acceptable binding agent). For
tablets or capsules, the carotenoid content such as the xanthophyll ester
content of the admixture is typically about 0.1 to about 25 milligrams
per tablet or capsule of carotenoid as can illustratively be measured as
free xanthophyll, and more usually about 5 to about 20 milligrams per
tablet or capsule.
[0103] Binding agents and adhesives preferably impart sufficient cohesion
to solids to permit normal processing such as sizing, lubrication,
compression and packaging, but still permit a tablet or capsule to
disintegrate and the composition to dissolve upon ingestion. Exemplary
binding agents include lactose monohydrate, acacia, tragacanth, sucrose,
gelatin, glucose, cellulose or saccharide materials such as, but not
limited to, microcrystalline cellulose, croscarmellose sodium,
hydroxypropyl methylcellulose (HPMC), hydroxypropyl cellulose
(Klucel.TM.), ethyl cellulose (Ethocel.TM.), methyl cellulose and sodium
carboxymethyl cellulose (e.g., Tylose.TM.), pregelatinized starch (such
as National.TM. 1511 and Starch 1500), polysaccharide acids, alginic acid
and salts of alginic acid, magnesium aluminum silicate, polyethylene
glycol, guar gum, bentonites, polyvinylpyrrolidone (povidone), and
polymethacrylates.
[0104] Exemplary edible oils include candelilia, coconut, cod liver,
cotton seed, menhaden, olive, palm, corn, soybean, peanut, poppy seed,
safflower and sunflower oil. The use of an oil having a relatively high
concentration of unsaturated fatty acids is preferred; i.e., the use of
an oil having an iodine value of about 100-150 is preferred. The
admixture is typically carried out using a high shear mixing apparatus,
as is well known. Co-solvents and additives such as ethanol and
.alpha.-tocopherol, respectively, can also be present as is noted in U.S.
Pat. No. 5,382,714.
[0105] In another embodiment, the mixture of zeaxanthin and lutein,
zeaxanthin alone, or other marigold-derived carotenoid compound such as
.beta.-carotene or lycopene, or a mixture is provided in the form of
generally spherical small pellets containing 0.5 to about 20 percent, and
preferably about 1 to about 4 percent, of the carotenoid that are
conventionally referred to as "beadlets". These beadlets can be used
admixed in a desired amount into human food such as ready to eat cereals
as is disclosed in U.S. Pat. No. 5,270,063 or admixed into chicken or
other animal feed as are the beadlets or other particles disclosed for
the feed additive in U.S. Pat. No. 5,849,345, No. 5,695,794, No.
5,605,699 and No. 5,043,170.
[0106] Exemplary beadlets are water-insoluble and are prepared by
encapsulation of a xanthophyll composition by cross-linked gelatin or an
alginate such as sodium alginate as is disclosed in U.S. Pat. No.
4,670,247. A water insoluble beadlet containing the desired carotenoid(s)
is prepared by forming an emulsion containing the carotenoid(s), water,
gelatin, and a sugar. The emulsion is converted into droplets that are
individually collected in a mass of starchy powder in such a manner that
the particles from the droplets are kept separated from each other until
their particulate form is permanently established. The
carotenoid-containing particles are separated from the starchy collecting
powder, and heat-treated at a temperature of about 90.degree. C. to about
180.degree. C. The heat treatment step insolubilizes the gelatin matrix
of the beadlet by a reaction between the carbonyl group of the sugar with
the free amino moieties of the gelatin molecule. The resulting beadlets
are water-insoluble and exhibit increased stability to the stresses of
feed pelleting. The cross-linking process utilizes the ingredients
employed in making the beadlet and does not require addition of a
cross-linking reagent or additive to the composition.
[0107] U.S. Pat. No. 5,695,794 discloses another form of beadlets that can
be adapted for use herein as an additive for poultry feed. Thus, beadlets
having diameters of about 30 to about 55 microns are prepared by spraying
a molten solution of a desired amount of carotenoid(s); i.e., zeaxanthin,
a mixture of zeaxanthin and lutein, or other carotenoid mixture described
herein, in hydrogenated vegetable oil such as hydrogenated cotton seed
oil, wheat-germ oil, safflower oil, soybean oil and the like, that also
can contain mono- and diglycerides such as those prepared from
hydrogenated soybean mono- and diglycerides, cottonseed mono- and
diglycerides and the like, as well as citric acid and
2,6-di-tert-butyl-4-methylphenol (BHT) as antioxidants. Other
antioxidants such as ethoxiquin, vitamin E and the like can also be used,
as is well known. The molten mixture is sprayed at a temperature of about
160.degree. F. (about 70.degree. C.) into a cyclonic airstream of a spray
chiller such as available from Niro, Inc., Columbia, Md. to produce the
beadlets that solidify on cooling. The cooled beadlets are dusted with an
anticaking agent such as fumed silica, calcium phosphate, powdered starch
or cellulose as are well known to form the beadlets that are preferably
added to the feed as supplement. An exemplary beadlet contains about 10
to about 100 milligrams of zeaxanthin per gram (mg/g) and preferably at
about 10 to about 50 mg/g.
[0108] Animal feeds to which a contemplated marigold-derived carotenoid
pigment such as zeaxanthin or a zeaxanthin-lutein, .beta.-carotene,
lycopene, or a mixture of such pigments are added are well known in the
art. The above-noted U.S. Pat. No. 5,849,345, No. 5,695,794, No.
5,605,699 and No. 5,043,170 provide exemplary diets that are particularly
useful for poultry. U.S. Pat. No. 5,935,624 and No. 2,918,370 provide
further illustrative poultry diets.
[0109] U.S. Pat. No. 5,258,189 teaches the addition of .beta.-carotene to
a ready to eat cereal product for humans in whom the .beta.-carotene is
admixed with a cooked cereal product dispersed in a vegetable oil or in
dry form. Zeaxanthin or a mixture of zeaxanthin and lutein as discussed
elsewhere herein can be used at a desired level in place of
.beta.-carotene in a similar food product.
[0110] Another composition suitable for use as a food or feed supplement
comprises a mixture of a marigold-derived carotenoid pigment such as
zeaxanthin and lutein, lycopene, phytoene, .beta.-carotene or the like
dissolved or dispersed in a comestible medium, wherein the zeaxanthin
ratio present is at a greater than about 1:10, preferably greater than
about 2:10, and up to about 1.0. This composition contains saponified
xanthophylls that are free zeaxanthin and lutein as compared to the
esters that are present in a marigold oleoresin.
[0111] The phrase "marigold-derived" is used herein for a carotenoid
pigment that is obtained from a mutant marigold as described herein.
Thus, substantially all (more than 90, and preferably more than 95
percent) of the carotenoid pigment present in a food or feed supplement
of marigold-derived carotenoid pigment is from a marigold, as compared to
being from another plant or produced synthetically. The pigment can be a
free carotene or xanthophyll (as shown in Table 10, hereinafter) or can
be a saponified xanthophyll.
[0112] Methods are well known for saponifiying marigold oleoresins to
provide free xanthophylls. See, for example, Tyczkowski et al., Poultry
Sci. 70(3): 651-654, 1991; and U.S. Pat. No. 5,382,714, that lutein was
crystallized from the saponified marigold oleoresin by the addition of
organic solvents.
[0113] In addition, Ausich et al. U.S. Pat. No. 5,648,564 teaches the
production of crystalline lutein from a marigold oleoresin by admixing
the oleoresin with a composition containing propylene glycol and an
aqueous alkali, preferably potassium hydroxide, to form a reaction
mixture of which oleoresin and propylene glycol together constitute at
least 75 weight percent. The reaction mixture so formed is maintained at
a temperature of about 65.degree. C. to about 80.degree. C. for a time
period (typically at least 3 hours) sufficient to saponify the
xanthophyll ester and form a saponified reaction mixture that contains
free xanthophyll in the form of crystals. The saponified extract is
admixed with a diluting amount of water to dissolve the water-soluble
impurities and reduce the viscosity of the reaction mixture. The diluted
admixture is gently admixed until homogeneous and then filtered to
collect the xanthophyll crystals. The collected xanthophyll crystals are
washed with warm water, and dried. No organic solvent other than
propylene glycol is used in the isolation and purification of the
xanthophyll from the xanthophyll ester-containing oleoresin. The dried
xanthophyll crystals so formed are typically admixed with a comestible
medium such as the triglyceride discussed above. The xanthophyll content
of the admixture is typically about 0.1 to about 35 percent by weight,
and preferably about one to about ten percent by weight.
[0114] Without further elaboration, it is believed that one skilled in the
art can, using the preceding description, utilize the present invention
to its fullest extent. The following preferred specific embodiments are,
therefore, to be construed as merely illustrative, and not limiting of
the remainder of the disclosure in any way whatsoever.
EXAMPLE 1
EMS Treatment of Tagetes erecta `Scarletade`
[0115] Seeds of Tagetes erecta xanthophyll marigold denominated
`Scarletade` (commercially available from PanAmerican Seed Co. 622 Town
Road, West Chicago, Ill. 60185) were treated with ethyl methanesulfonate
(EMS, commercially available from Sigma Chemical Co., St. Louis, Mo.
63178). Approximately 2,500 seeds were added to 400 ml of 0.4% (v/v) or
0.8% (v/v) EMS and were stirred gently for eight hours at ambient
temperature. During a four-hour period following the EMS treatment, the
seeds were washed sixteen times, each wash using continuous stirring with
400 ml distilled water. The treated seeds, identified as M.sub.1 seeds,
were then sown in trays containing
soilless potting mix.
[0116] After several weeks, the seedlings were transplanted into pots
containing
soilless potting mix and maintained in the greenhouse. Flowers
produced by those plants were naturally self-pollinated. The resulting
seeds, identified as M.sub.2 seeds, were harvested from approximately
2,300 plants. Of these 2,300 plants, approximately 1,500 were grown from
seeds treated with 0.4% EMS and approximately 800 were grown from seeds
treated with 0.8% EMS. To facilitate identification of mutant plants, the
M.sub.2 seeds from each of 50 M.sub.1 plants were combined into one lot,
resulting in a total of 47 seed lots. During the summer of the year 2000,
500 seeds from each of the 47 lots were sown and the resulting plants
were field-grown at PanAmerican Seed Co. in Santa Paula, Calif. 93060.
EXAMPLE 2
HPLC Screening of EMS-Treated Tagetes erecta `Scarletade`
[0117] EMS-treated `Scarletade` plants were field-grown at PanAmerican
Seed Co. in Santa Paula, Calif. 93060, and were screened by HPLC for
altered zeaxanthin ratio. Flowers approximately 98% fully opened were
selected for analysis. From each flower, one petal was removed one-third
of the distance from the flower center and placed in a 3.5''.times.0.75''
glass vial containing approximately 5 grams of glass beads. Vials were
packaged with dry ice until stored at -80.degree. C.
[0118] For analysis, solvent delivery and aliquot removal were
accomplished with a robotic system comprising a single injector valve
Gilson 232XL and a 402 2S1V diluter [Gilson, Inc. USA, 3000 W. Beltline
Highway, Middleton, Wis.]. For saponification, 3 ml of 50% potassium
hydroxide hydro-ethanolic solution (4 water:1 ethanol) was added to each
vial, followed by the addition of 3 ml of octanol. The saponification
treatment was conducted at room temperature with vials maintained on an
IKA HS 501 horizontal shaker [Labworld-online, Inc. Wilmington, N.C.] for
fifteen hours at 250 movements/minute, followed by a stationary phase of
approximately one hour.
[0119] Following saponification, the supernatant was diluted with 0.9 ml
of methanol. The addition of methanol was conducted under pressure to
ensure sample homogeneity. Using a 0.25 ml syringe, a 0.1 ml aliquot was
removed and transferred to HPLC vials for analysis.
[0120] For HPLC analysis, a Hewlett Packard 1100 HPLC, complete with a
quaternary pump, vacuum degassing system, six-way injection valve,
temperature regulated autosampler, column oven and Photodiode Array
detector was used [Agilent Technologies available through Ultra
Scientific Inc., 250 Smith Street, North Kingstown, R.I.]. The column was
a Waters YMC 30, 5-micron, 4.6.times.250 mm with a guard column of the
same material [Waters, 34 Maple Street, Milford, Mass.]. The solvents for
the mobile phase were 81 methanol: 4 water: 15 tetrahydrofuran (THF)
stabilized with 0.2% BHT (2,6-di-tert-butyl-4-methylphenol). Injections
were 20 .mu.l. Separation was isocratic at 30.degree. C. with a flow rate
of 1.7 ml/minute. The peak responses were measured by absorbance at 447
nm.
[0121] Using this protocol, the results from the first 2,546 samples were
statistically analyzed to establish average values for lutein and
zeaxanthin content. Because this was a semi-quantitative analytical
screen, peak area values were used. To identify a mutant having a higher
than average lutein and/or zeaxanthin concentration, a value of three
standard deviations greater than the average was calculated. The
calculated peak area means, standard deviations and zeaxanthin ratios are
shown in Table 1, below.
TABLE-US-00001
TABLE 1
Lutein and Zeaxanthin Confidence Interval
Calculations
Peak Area Peak Area
Statistic Lutein Zeaxanthin Ratio (%)
Mean 775.0 41.6 5.03
Standard 263.2 16.4 0.71
deviation (sd)
Mean + 3 sd 1564.6 90.9 7.16
[0122] Based on the above values, samples were selected having lutein peak
areas greater than 1565 and/or zeaxanthin peak areas greater than 91.
Samples were also selected only for high lutein peak area, and for
zeaxanthin ratios greater than 10 percent. A total of 88 mutants were
identified from 21,754 assayed samples using these selection parameters.
The total number of mutants resulting from each EMS seed treatment is
shown in Table 2, below.
TABLE-US-00002
TABLE 2
Correlation of `Scarletade` Mutants to EMS Treatment
Selection 0.4% EMS 0.8% EMS Total
Parameter Treatment Treatment Plants
Zeaxanthin Ratio > 10% 10 13 23
Lutein > 1566 and 18 10 28
Zeaxanthin > 91
Lutein > 1566 and 20 7 27
Zeaxanthin < 91
Lutein < 1566 and 7 3 10
Zeaxanthin > 91
[0123] More specific results of those assays as to relative levels of
lutein and zeaxanthin are shown in Table 3, below.
TABLE-US-00003
TABLE 3
Identified `Scarletade` Mutants
Plant Lutein Zeaxanthin Percent Percent
Identifier Area Area Zeaxanthin EMS Used
124-257 2.115 55.635 96.34 0.4
119-494 9.254 131.036 93.40 0.8
112-263 8.095 35.273 81.33 0.4
118-036 11.441 31.691 73.47 0.8
088-452 2.94 6.689 69.47 0.4
118-035 11.289 23.951 67.97 0.8
114-334 58.24 97.968 62.72 0.4
117-185 39.002 44.027 53.03 0.8
108-108 13.424 10.155 43.07 0.4
088-425 8.959 4.394 32.91 0.4
094-238 7.285 3.063 29.60 0.4
110-308 46.753 14.248 23.36 0.4
132-346 31.036 8.856 22.20 0.8
100-334 282.987 54.298 16.10 0.8
101-331 246.402 46.467 15.87 0.8
100-198 119.381 21.449 15.23 0.8
101-190 139.027 23.125 14.26 0.8
114-315 351.524 56.898 13.93 0.4
100-470 189.703 27.743 12.76 0.8
117-348 369.903 43.315 10.48 0.8
132-266 374.096 43.8 10.48 0.8
123-310 60.743 6.818 10.09 0.4
116-106 453.538 50.287 9.98 0.8
[0124] About 21,700 plants exhibited typical zeaxanthin ratios of about 4
to about 7 percent (about 1:25 to about 1:15). The above data illustrate
the relative rarity of the mutations contemplated, as well as the almost
equal number of plants that exhibit reduced zeaxanthin levels. The data
also do not show a preference for the use of one level of mutagen versus
the other used here.
EXAMPLE 3
EMS Treatment of Tagetes erecta 13819
[0125] Seeds of Tagetes erecta xanthophyll marigold named 13819 (a
proprietary breeding selection of PanAmerican Seed Co. 622 Town Road,
West Chicago, Ill. 60185) were treated with ethyl methanesulfonate (EMS,
commercially available from Sigma Chemical Co. St. Louis, Mo. 63178).
Approximately, 7,000 seeds were added to 600 ml of 0.2% (v/v) or 0.4%
(v/v) EMS and stirred gently for eight hours at ambient temperature.
During a four-hour period following the EMS treatment, the seeds were
washed sixteen times, each wash using continuous stirring with 600 ml
distilled water.
[0126] The treated seeds, identified as M.sub.1 seeds, were then sown in
trays containing soilless potting mix. After three to four weeks, the
seedlings were transplanted into the field. Flowers produced by these
plants were bagged to prevent cross-pollination, and were permitted to
spontaneously self-pollinate. The resulting seeds, identified as M.sub.2
seeds, were harvested from approximately 2,391 plants. Of these plants,
approximately 951 were grown from seeds treated with 0.2% EMS and
approximately 1,440 were grown from seeds treated with 0.4W EMS.
[0127] To facilitate identification of mutant plants, the M.sub.2 seeds
from each of 50 plants were combined into one lot. This grouping resulted
in a total of 48 seed lots. From late October through mid-November of the
year 2000, 1000 seeds from each of 15 lots of the 0.4% EMS treatment were
sown and 700 plants of each lot were greenhouse-grown at Seaview Nursery
in El Rio, Calif. 93060. In addition, 1,500 seeds from all of the 48 lots
were sown in late October of the year 2000, and 765 plants from each of
the lots were field-grown at Semillas Pan American Chile LTDA, in
Pichidegua, Chile.
EXAMPLE 4
HPLC Screening of EMS-Treated Tagetes erecta 13819
[0128] EMS-treated 13819 M.sub.2 plants were greenhouse-grown at Seaview
Nursery in El Rio, Calif. 93060 and field-grown at Semillas PanAmerican
Chile LTDA, in Pichidegua, Chile, and were screened for altered
zeaxanthin ratio. Flowers approximately 98% fully opened were selected
for analysis. From these flowers, petals were removed one-third of the
distance from the flower center. Approximately 100 mg of petal tissue was
placed in plastic bags and stored frozen until analysis. Dry weight was
determined for two petals that were placed in 3.5''.times.0.75'' glass
vials containing approximately 5 grams of glass beads.
[0129] For analysis, solvent delivery and aliquot removal were
accomplished with a robotic system comprising a single injector valve
Gilson 232XL and a 402 2S1V diluter. For saponification, 3 ml of 50%
potassium hydroxide hydro-ethanolic solution (4 water:1 ethanol) was
added to each vial, followed by the addition of 3 ml octanol. The
saponification treatment was conducted at room temperature with vials
maintained on an IKA HS 501 horizontal shaker for fifteen hours at 250
movements per minute followed by a stationary phase of approximately one
hour.
[0130] Following saponification, the supernatant was diluted with 0.9 ml
of methanol. The addition of methanol was conducted under pressure to
ensure sample homogeneity. Using a 0.25 ml syringe, a 0.1 ml aliquot was
removed and transferred to HPLC vials for analysis.
[0131] For HPLC analysis, a Hewlett Packard 1100 complete with a
quaternary pump, vacuum degassing system, six-way injection valve,
temperature regulated autosampler, column oven and P
hotodiode Array
detector was used. The column was a Waters YMC 30, 5-micron,
4.6.times.250 mm with a guard column of the same material. Standards were
obtained from DHI-Water & Environment, DK-2970 Horsholm, Denmark and
Sigma Chemical Co., St. Louis, Mo. 63178. The solvents for the mobile
phase were 81 methanol:4 water:15 tetrahydrofuran stabilized with 0.2%
BHT. Injections were 20 .mu.l. Separation was isocratic at 30.degree. C.
with a flow rate of 1.7 ml/minute. The peak responses were measured at
447 nm.
[0132] Using this protocol, the results from the first 507 samples were
statistically analyzed to establish average values for lutein and
zeaxanthin content. To identify a mutant having a higher or lower than
average lutein and zeaxanthin concentration, a value of three standard
deviations greater than or less than the average was calculated. The
calculated means, standard deviations and zeaxanthin ratios are shown in
Table 4, below.
TABLE-US-00004
TABLE 4
Lutein and Zeaxanthin Confidence Interval
Calculations
Lutein Lutein +
mg/g Zeaxanthin Zeaxanthin
Fresh mg/g Fresh mg/g Fresh Ratio
Statistic Weight Weight Weight (%)
Mean 0.64 0.04 0.68 5.98
Standard 0.14 0.01 0.147 1.1
deviation
Mean + 3 sd 1.06 0.07 1.12 9.28
Mean - 3 sd 0.22 0.007 0.24 2.68
[0133] Based on the above values, samples were selected having zeaxanthin
ratios greater than 10 percent, combined lutein and zeaxanthin content
greater than 1.12 mg/g fresh weight and combined lutein and zeaxanthin
content less than 0.24 mg/g fresh weight. A total of 347 mutants were
identified having a sum of lutein plus zeaxanthin greater than 1.12 mg/g,
and 43 mutants having a zeaxanthin ratio greater than 10 percent were
identified from 8192 samples using these selection parameters. The total
number of mutants resulting from each EMS seed treatment is shown in
Table 5, below.
TABLE-US-00005
TABLE 5
Correlation of 13819 Mutants to EMS Treatment
0.2% EMS 0.4% EMS Total
Selection Parameter Treatment Treatment Plants
Zeaxanthin 2 41 43
Ratio > 10%
Lutein + Zeaxanthin > 1.12 mg/g 6 341 347
dry weight
Lutein + Zeaxanthin < 0.24 mg/g 2 175 177
dry weight
[0134] Of the mutants having a zeaxanthin ratio greater than about 10
percent zeaxanthin, about 47 percent had between 10 and under 13 percent,
whereas 53 percent exhibited 13 percent or greater.
EXAMPLE 5
Carotenoid Composition in Petals of Select Marigolds
[0135] Carotenoid compositions were determined for `Scarletade` wild-type
and mutant samples selected from those identified in the screening
procedure described in Example 2. Petal samples were stored in a
-80.degree. C. freezer until mutants were identified. Samples were
lyophilized, and the dried tissue was stored under argon at -80.degree.
C. until ready for analysis.
[0136] Extraction procedures were performed under red light. Dried petals
were ground to pass through a No. 40 sieve mesh size. A ground sample was
accurately weighed and transferred into a 100 ml red volumetric flask. To
the sample, 500 microliters (.mu.l) of H.sub.2O were added, and the
mixture was swirled for 1 minute. Thirty ml of extractant solvent (10 ml
hexane+7 ml acetone+6 ml absolute alcohol+7 ml toluene) were added, and
the flask was shaken at 160 rpm for 10 minutes.
[0137] For saponification, 2 ml of 40% methanolic KOH were added into the
flask, which was then swirled for one minute. The flask was placed in a
56.degree. C. H.sub.2O bath for 20 minutes. An air condenser was attached
to prevent loss of solvent. The sample was cooled in the dark for one
hour with the condenser attached. After cooling, 30 ml of hexane were
added, and the flask was shaken at 160 rpm for 10 minutes.
[0138] The shaken sample was diluted to volume (100 ml) with lot sodium
sulfate solution and shaken vigorously for one minute. The sample
remained in the dark for at least 30 minutes. A 35 ml aliquot was removed
from the approximately 50 ml upper phase, and transferred to a sample
cup. An additional 30 ml of hexane were added into the flask that was
then shaken at 160 rpm for 10 minutes. After approximately one hour, the
upper phases were combined. For HPLC analysis, 10 ml aliquots were dried
under nitrogen and stored under argon at -80.degree. C.
[0139] HPLC equipment comprised an Alliance 2690 equipped with a
refrigerated autosampler, column heater and a Waters P
hotodiode Array 996
detector (Waters Corp., 34 Maple Street Milford, Mass. 01757). Separation
was obtained with a YMC C30 column, 3 .mu.m, 2.0.times.150 mm with a
guard column of the same material. Standards were obtained from ICC
Indofine Chemicals Somerville, N.J. 088876 and from DHI-Water &
Environment, DK-2970 Horsholm, Denmark.
[0140] The dried mutant samples were resuspended in tetrahydrofuran and
methanol to a total volume of 200 .mu.l and filtered, whereas the control
was not additionally concentrated. Carotenoids were separated using a
gradient method. Initial gradient conditions were 90% methanol: 5% water:
5% methyl tert-butyl ether at a flow rate of 0.4 milliliters per minute
(ml/min). From zero to 15 minutes, the mobile phase was changed from the
initial conditions to 80 methanol: 5 water: 15 methyl tert-butyl ether,
and from 15 to 60 minutes to 20 methanol: 5 water: 75 methyl tert-butyl
ether. For the following 10 minutes, the mobile phase was returned to the
initial conditions and the column equilibrated for an additional 10
minutes. The column temperature was maintained at 27.degree. C. and the
flow rate was 0.4 ml/minute. Injections were 10 .mu.l. The majority of
peak responses were measured at 450 nm and additional areas added from
286, 348, 400 and 472 nm extracted channels.
[0141] Values for carotenoid profiles of selected mutants are indicated in
Tables 6a, 6b and 6c, below, using peak area as percent of the total
area. Indicated compound identifications are based on spectra extracted
and maximal absorbance in ethanol (lambda-maxima; ETOH) obtained for
major peaks in each chromatogram, some of which were verified by
retention times of known standards. Values combine suspected isomers of
the same compounds. Some compounds may contain minor impurities. Included
in the Table are values for yellow colored American marigolds (yellow
marigold) noted in Quackenbush et al., J. Assoc. Off. Anal. Chem.,
55(3):617-621 (1972). Single entries are used in Tables 6a-6c for
neoxanthin/violaxanthin and chrysanthemaxanthin/flavoxanthin compound
pairs that could not be separated by the procedure used here.
TABLE-US-00006
TABLE 6a
Relative Percent Distribution of Carotenoids
In Petals of Tagetes erecta and Mutants
Wave-
length Marigold Selections
in EtOH Yellow
Carotenoid (nm) Marigold `Scarletade` 13819 117-185 124-257 119-494
112-263 118-035 088-425 325-444
Phytoene 276, 286, 2.4 0.3 0.3 6.8 7.0 1.0 11.0 12.3 34.3 30.9
297
Phytofluene 331, 348, 2.6 0.5 0.4 4.0 4.2 0.9 7.5 7.4 17.8 13.3
(isomers) 367
.zeta.-Carotene 377, 399, nf* <0.1 <0.1 5.6 5.3 1.3 6.9 6.8 18.2
17.1
(cis/trans 425
isomers)
Neurosporene 416, 440, nr** <0.1 <0.1 0.1 0.2 <0.1 <0.1
<0.1 3.5 3.5
470
Lycopene 447, 472, nr <0.1 <0.1 0.5 1.3 <0.1 <0.1 <0.1 1.0
2.8
504
.alpha.-Carotene 423, 444, 0.1 <0.1 <0.1 <0.1 <0.1 <0.1
<0.1 <0.1 0.8 1.2
473
.beta.-Carotene 425, 451, 0.5 <0.1 <0.1 4.4 6.8 2.3 0.6 0.3 2.3 4.8
478
Neoxanthin 415, 439, 0.8 1.5 4.1 13.3 12.8 16.7 4.3 3.5 0.7 1.1
467
Violaxanthin 419, 440, nr
470
Antheraxanthin 422, 444, 0.1 3.1 5.5 12.5 14.4 19.2 4.1 4.5 0.9 1.5
472
Lutein 420, 445, 72.3 84.9 81.7 13.3 1.3 <0.1 0.6 7.1 2.0 4.9
475
Zeaxanthin 428, 450, 16.4 4.7 5.9 21.3 30.6 35.7 16.5 18.2 2.0 4.0
478
.alpha.-Cryptoxanthin 421, 446, 0.8 <0.1 <0.1 <0.1 <0.1
<0.1 32.2 26.9 <0.1 0.2
475
.beta.-Cryptoxanthin 428, 450, 0.5 <0.1 <0.1 0.5 0.6 0.8 0.2 0.4 1.9
1.8
478
.beta.-Zeacarotene 406, 428, 0.5 not identified
454
Chrysanthemaxanthin 400, 421, 0.8 <0.1 <0.1 2.3 1.5 4.5 0.8 0.5 0.2
0.2
448
Flavoxanthin 400, 421, 1.3
448
Auroxanthin 380, 401, 0.1 not identified
426
Other compounds that 0.8 5.0 2.1 15.3 14.0 17.6 15.1 12.0 14.3 12.7
show absorbance at 450 nm
*nf = not found
**nr = not reported
[0142]
TABLE-US-00007
TABLE 6b
Relative Percent Distribution of Carotenoids In
Petals of Tagetes erecta and Mutants
Wave-
length in Marigold Selections
Carotenoid EtOH (nm) Yellow Marigold `Scarletade` 13819 100-198 100-334
100-470 101-190 114-315
Phytoene 276, 286, 2.4 0.3 0.3 4.8 3.9 6.1 3.4 5.2
(isomers) 297
Phytofluene 331, 348, 2.6 0.5 0.4 3.2 3.2 3.8 3.2 3.3
(isomers) 367
.zeta.-Carotene 377, 399, nf* <0.1 <0.1 4.8 4.0 4.4 3.6 3.2
(cis/trans 425
isomers)
Neurosporene 416, 440, nr** <0.1 <0.1 <0.1 <0.1 <0.1
<0.1 <0.1
470
Lycopene 447, 472, nr <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
<0.1
504
.alpha.-Carotene 423, 444, 0.1 <0.1 <0.1 0.3 0.4 0.2 0.4 0.2
473
.beta.-Carotene 425, 451, 0.5 <0.1 <0.1 0.8 0.7 0.5 0.8 0.5
478
Neoxanthin 415, 439, 0.8 1.5 4.1 <0.2 0.3 <0.2 <0.2 <0.2
467
Violaxanthin 419, 440, nr
470
Antheraxanthin 422, 444, 0.1 3.1 5.5 <0.2 <0.2 <0.2 <0.2
<0.2
472
Lutein 420, 445, 72.3 84.9 81.7 68.0 70.7 67.5 71.1 71.6
475
Zeaxanthin 428, 450, 16.4 4.7 5.9 14.8 13.4 13.1 13.6 12.3
478
.alpha.-Cryptoxanthin 421, 446, 0.8 <0.1 <0.1 0.6 0.6 0.5 0.6 0.4
475
.delta.-Carotene 431, 456, nr <0.1 <0.1 0.5 0.2 0.8 0.4 0.5
489
.beta.-Cryptoxanthin 428, 450, 0.5 <0.1 <0.1 <0.2 <0.2 <0.2
<0.2 <0.2
478
.beta.-Zeacarotene 406, 428, 0.5 not identified
454
Chrysanthemaxanthin 400, 421, 0.8 <0.1 <0.1 <0.2 <0.2 <0.2
<0.2 <0.2
448
Flavoxanthin 400, 421, 1.3
448
Auroxanthin 380, 401, 0.1 not identified
426
Other compounds that 0.8 5.0 2.1 2.1 2.6 2.9 2.8 2.7
show absorbance at 450 nm
*nf = not found
**nr = not reported
[0143]
TABLE-US-00008
TABLE 6c
Relative Percent Distribution of Carotenoids In
Petals of Tagetes erecta and Mutants
Wave-
length in Marigold Selections
Carotenoid EtOH (nm) Yellow Marigold `Scarletade` 13819 126-415 098-240
098-394 115-004
Phytoene 276, 286, 2.4 0.3 0.3 11.8 10.0 8.6 13.0
(isomers) 297
Phytofluene 331, 348, 2.6 0.5 0.4 9.1 5.8 5.4 9.6
(isomers) 367
.zeta.-Carotene 377, 399, nf* <0.1 <0.1 5.0 3.6 3.5 10.3
(cis/trans 425
isomers)
Neurosporene 416, 440, nr** <0.1 <0.1 <0.1 <0.1 <0.1
<0.1
470
Lycopene 447, 472, nr <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
504
.alpha.-Carotene 423, 444, nr <0.1 <0.1 0.5 0.4 0.4 0.6
473
.beta.-Carotene 425, 451, 0.5 <0.1 <0.1 0.1 0.1 0.1 <0.1
478
Neoxanthin 415, 439, 0.8 1.5 4.1 0.3 0.4 0.4 <0.1
467
Violaxanthin 419, 440, nr
470
Antheraxanthin 422, 444, 0.1 3.1 5.5 1.7 1.9 2.2 1.9
472
Lutein 420, 445, 72.3 84.9 81.7 61.7 70.1 71.0 52.3
475
Zeaxanthin 428, 450, 16.4 4.7 5.9 2.5 2.8 3.4 1.8
478
.alpha.-Cryptoxanthin 421, 446, 0.8 <0.1 <0.1 0.7 0.6 0.4 0.2
475
.delta.-Carotene 431, 456, nr <0.1 <0.1 1.6 0.4 0.3 5.2
489
.beta.-Cryptoxanthin 428, 450, 0.1 <0.1 <0.1 <0.1 <0.1 <0.1
<0.1
478
.beta.-Zeacarotene 406, 428, 0.5 not identified
454
Chrysanthemaxanthin 400, 421, 0.8 <0.1 <0.1 <0.1 0.1 0.1 <0.1
448
Flavoxanthin 400, 421, 1.4
448
Auroxanthin 380, 401, 0.1 not identified
426
Other compounds that 0.8 5.0 2.1 4.9 3.7 4.19 4.8
show absorbance at 450 nm
*nf = not found
**nr = not reported
EXAMPLE 6
Carotenoid Composition in Leaves of Select Marigolds
[0144] Leaves of several marigold plants were assayed for the relative
concentration of colored carotenoids present. Leaves from `Scarletade`
and 13819 were used as controls for comparison to leaves from mutant
plants. Assays were conducted as in Example 5 and are shown in Tables 7a
and 7b, below, where single entries are used for neoxanthin/violaxanthin
and chrysanthemaxanthin/flavoxanthin compound pairs that could not be
separated. Data in Tables 7a and 7b were collected from different groups
of plants grown under different conditions.
TABLE-US-00009
TABLE 7a
Relative Percent Distribution of Carotenoids in
Leaves of Tagetes erecta and Mutants
Wave-
length in Marigold Selections
Carotenoid EtOH (nm) `Scarletade` 13819 124-257 119-494 117-185 086-013
Phytoene 276, 286, 0.1 0.4 0.5 0.2 0.2 0.5
297
Neoxanthin 415, 439, 9.2 17.6 36.3 22.7 26.8 11.6
467
Violaxanthin 419, 440,
470
Antheraxanthin 422, 444, 2.8 4.3 8.4 7.7 9.1 2.9
472
Lutein 420, 445, 44.3 37.8 0.5 <0.1 1.6 34.0
475
Zeaxanthin 428, 450, 6.6 3.8 4.6 27.5 10.6 4.1
478
.beta.-Carotene 425, 451, 22.6 26.5 34.1 25.0 32.7 35.8
478
.alpha.-Carotene 423, 444, 0.5 0.3 <0.1 <0.1 <0.1 0.2
473
Chrysanthemaxanthin 400, 421, 1.1 1.0 0.9 4.1 3.2 0.5
448
Flavoxanthin 400, 421,
448
Other compounds that 12.8 8.3 14.7 12.7 15.8 10.4
show absorbance at 450 nm
[0145]
TABLE-US-00010
TABLE 7b
Relative Percent Distribution of Carotenoids in
Leaves of Tagetes erecta and Mutants
Wave-
length in Marigold Selections
Carotenoid EtOH (nm) `Scarletade` 100-198 100-334 100-470 101-190 114-315
Phytoene 276, 286, Inadequate Peak Separation
297
Neoxanthin 415, 439, 20.4 <0.1 0.3 <0.1 3.1 <0.1
467
Violaxanthin 419, 440,
470
Antheraxanthin 422, 444, 1.6 1.7 1.8 1.6 5.4 1.1
472
Lutein 420, 445, 48.3 24.7 27.6 28.8 27.7 24.3
475
Zeaxanthin 428, 450, 0.4 46.3 43.1 44.0 32.3 48.2
478
.beta.-Carotene 425, 451, 15.9 14.5 17.3 14.5 19.6 13.8
478
.alpha.-Carotene 423, 444, <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
473
Chrysanthemaxanthin 400, 421, 1.0 <0.1 <0.1 <0.1 <0.1 <0.1
448
Flavoxanthin 400, 421,
448
.beta.-Cryptoxanthin 428, 450, 0.3 0.3 0.3 0.6 0.3 0.9
478
Other compounds that show 12.1 12.4 9.5 10.5 11.5 11.7
absorbance at 450 nm
EXAMPLE 7
Preparation of Marigolds with Little Lutein and High Zeaxanthin, Phytoene,
Lycopene or .beta.-Carotene Levels Through Breeding of Mutants
[0146] Marigold mutant selection 124-257 that exhibits an increased
zeaxanthin to lutein ratio compared to wild type was selfed and the
resulting seed was maintained. Plants from the selfing of marigold
selection 124-257 were used as male parents in a cross with female parent
PanAmerican Seed proprietary breeding line F9 Ap (85368-4). From this
cross, F.sub.1 plants were produced and selfed to yield an F.sub.2
population.
[0147] Fifteen seedlings from the F.sub.2 cross were analyzed for the
absence of lutein using thin layer chromatography (TLC). Approximately 50
mg of fresh leaf tissue from each seedling was weighed into a
100.times.13 mm screw top tube containing five glass beads. Sealed vials
were stored at -20.degree. C.
[0148] For analysis, 500 .mu.l of extractant solvent (10 ml hexane+7 ml
acetone+6 ml absolute alcohol+7 ml toluene) were added, and the sealed
tubes were vortexed for a minimum of 45 minutes. After vortexing, the
solution was transferred to a 4 ml amber vial and evaporated under
nitrogen. Samples were resuspended in 125 .mu.l of the above-described
extraction solvent and 10 .mu.l were spotted on 19 channel silica gel
plates. Plates were dried for approximately 10 minutes then developed for
25 minutes in a two channel 25 cm developing tank containing 100 ml of a
2:1 ethyl acetate:hexane solution. Upon removal, samples were evaluated
for the absence of lutein.
[0149] From this screen, F.sub.2 marigold selection 14649-3 was
identified. This selection was used as the female parent in crosses with
mutants 101-190 and 100-198, which exhibit an increased zeaxanthin to
lutein ratio in addition to having reduced epoxycarotenoid (e.g.,
neoxanthin and violaxanthin) production compared to wild type.
[0150] Marigold mutant selection 100-198 was selfed and the resulting seed
was maintained. Plants from the selfing of marigold selection 100-198
were used as the male parent in a cross with the female parent selection
14649-3 described above. From this cross, F.sub.1 seeds were collected,
and of these 30 seeds were planted. Eleven of the resulting plants were
selfed. From this cross, F.sub.2 seeds were collected, and 400 of those
seeds were planted and grown.
[0151] TLC analysis, as described above, was used to analyze leaves of 151
seedlings. Thirty-two plants were identified based on reduced
epoxycarotenoid production typical of mutant selection 100-198. The
remaining TLC extract was analyzed using high performance liquid
chromatography (HPLC), performed using a modified Example 5 protocol.
Modifications include the following: dried samples were resuspended into
methyl tert-butyl ether and methanol, all gradient conditions used water
increased to 6% with a corresponding 1% decrease in methanol, and column
temperature was maintained at 25.degree. C.
[0152] Analysis confirmed that seven of the 32 plants exhibited an
increased zeaxanthin to lutein ratio typical of mutant selection 124-257.
Petal and leaf samples of the seven selections were extracted and
analyzed according to the protocol in Example 5 with modifications noted
above. The results for petals are shown in Table 8a, below, and results
for leaves are shown in Table 9a thereafter. In addition, non-saponified
petal samples were analyzed to determine the percentage, if any, of
non-esterified zeaxanthin. Those data are presented in Table 10.
[0153] Marigold mutant selection 101-190 was selfed and the resulting seed
was maintained. Marigold selection 101-190 was used as the male parent in
a cross with the female parent selection 14649-3 described above. From
this cross, F.sub.1 seeds were collected and of those seeds, 30 were
planted. Six of the resulting plants were selfed. From this latter cross,
F.sub.2 seeds were collected, planted and grown.
[0154] It was determined that the current TLC analysis method was
inconclusive for this population. Therefore, approximately 30 plants were
selected for HPLC analysis based on having an orange-colored sepal
phenotype.
[0155] Samples were extracted as for TLC; however, HPLC analysis was
conducted. Ten of the 30 selections were found to have reduced
epoxy-carotenoid production typical of mutant selection 101-190 in
addition to having an increased zeaxanthin to lutein ratio typical of
selection 124-257.
[0156] Petal and leaf samples of the ten selections were extracted and
analyzed according to the protocol in Example 5 with modifications noted
above. The results for petals are shown in Tables 8b and 8c, and results
for leaves are shown in Tables 9b and 9c. In addition, non-saponified
petal samples were analyzed to determine the percentage of non-esterified
zeaxanthin. Those data are presented in Table 10.
TABLE-US-00011
TABLE 8a
Relative Percent Distribution of Carotenoids
In Petals of Tagetes erecta and Mutant Crosses
Wave-
length
in EtOH Marigold Selections
Carotenoid (nm) `Scarletade` 124-257 100-198 27772-029 27772-036 27772-100
27772-109 27772-123 27772-130 27772-134
Phytoene 276, 286, 0.5 3.9 4.5 4.9 9.2 7.0 5.1 5.6 5.7 11.7
(isomers) 297
Phytofluene 331, 348, 0.7 3.6 4.4 4.6 7.2 5.7 4.6 5.3 5.0 8.2
(isomers) 367
.zeta.-Carotene 377, 399, <0.2 3.3 4.1 4.8 10.6 5.2 4.5 5.0 4.4 7.4
(cis/trans 425
isomers)
Neurosporene 416, 440, <0.2 <0.2 <0.2 0.2 0.4 0.3 <0.2 0.2 0.3
0.4
470
Lycopene 447, 472, <0.2 0.5 <0.2 0.3 1.4 0.9 <0.2 0.6 0.3 0.9
504
.alpha.-Carotene 423, 444, <0.2 <0.2 0.4 <0.2 <0.2 <0.2
<0.2 <0.2 <0.2 <0.2
473
.beta.-Carotene 425, 451, <0.2 7.4 1.3 6.3 6.1 4.9 4.5 4.2 5.0 4.8
478
Neoxanthin 415, 439, 0.5 3.4 <0.2 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2 <0.2
467
Violaxanthin 419, 440, 0.7 12.7 <0.2 <0.2 <0.2 <0.2 <0.2
<0.2 0.2 <0.2
470
Antheraxanthin 422, 444, 1.6 17.5 0.6 0.5 0.4 0.6 0.5 0.5 0.7 0.3
472
Lutein 420, 445, 91.0 2.3 68.1 0.5 0.5 0.5 0.4 0.4 0.6 0.4
475
Zeaxanthin 428, 450, 3.3 29.8 14.3 73.8 60.0 70.3 76.5 74.3 72.4 62.0
478
.alpha.-Cryptoxanthin 421, 446, <0.2 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2 <0.2 <0.2 <0.2
475
.delta.-Carotene 431, 456, <0.2 <0.2 0.7 <0.2 <0.2 <0.2
<0.2 <0.2 0.3 <0.2
489
.beta.-Cryptoxanthin 428, 450, <0.2 1.0 <0.2 1.1 1.0 1.1 1.4 1.1 1.1
1.1
478
.beta.-Zeacarotene 406, 428, not identified
454
Chrysanthema- 400, 421, <0.2 1.7 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2 <0.2 <0.2
xanthin 448
Flavoxanthin 400, 421,
448
Auroxanthin 380, 401, not identified
426
Other compounds that 1.7 12.9 1.6 2.8 3.2 3.5 2.4 2.7 4.2 2.8
show absorbance at 450 nm
[0157]
TABLE-US-00012
TABLE 8b
Relative Percent Distribution of Carotenoids
In Petals of Tagetes erecta and Mutant Crosses
Wave-
length in Marigold Selections
Carotenoid EtOH (nm) `Scarletade` 124-257 101-190 27773-006 27773-030
27773-087 27773-107 27773-128
Phytoene 276, 286, 0.5 3.9 3.9 3.2 5.9 6.8 8.3 4.9
(isomers) 297
Phytofluene 331, 348, 0.7 3.6 4.6 3.8 5.8 7.2 7.3 4.9
(isomers) 367
.zeta.-Carotene 377, 399, <0.2 3.3 5.1 4.4 5.0 10.4 8.6 5.0
(cis/trans 425
isomers)
Neurosporene 416, 440, <0.2 <0.2 <0.2 <0.2 0.2 <0.2 <0.2
<0.2
470
Lycopene 447, 472, <0.2 0.5 <0.2 0.2 0.4 0.8 <0.2 0.4
504
.alpha.-Carotene 423, 444, <0.2 <0.2 0.3 <0.2 <0.2 <0.2
<0.2 <0.2
473
.beta.-Carotene 425, 451, <0.2 7.4 1.6 9.8 8.9 11.7 8.0 7.1
478
Neoxanthin 415, 439, 0.5 3.4 <0.2 <0.2 <0.2 <0.2 <0.2
<0.2
467
Violaxanthin 419, 440, 0.7 12.7 <0.2 <0.2 <0.2 <0.2 <0.2
<0.2
470
Antheraxanthin 422, 444, 1.6 17.5 0.6 1.9 1.8 0.9 0.8 2.1
472
Lutein 420, 445, 91.0 2.3 63.8 0.8 0.6 0.9 0.7 0.6
475
Zeaxanthin 428, 450, 3.3 29.8 16.8 69.4 67.9 58.5 62.4 70.3
478
.alpha.-Cryptoxanthin 421, 446, <0.2 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2 <0.2
475
.delta.-Carotene 431, 456, <0.2 <0.2 0.2 0.9 <0.2 0.2 0.4 <0.2
489
.beta.-Cryptoxanthin 428, 450, <0.2 1.0 0.2 1.1 1.2 1.1 1.5 1.3
478
.beta.-Zeacarotene 406, 428, not identified
454
Chrysanthemaxanthin 400, 421, <0.2 1.7 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2
448
Flavoxanthin 400, 421,
448
Auroxanthin 380, 401, not identified
426
Other compounds that 1.7 12.9 2.8 4.1 2.2 1.5 1.7 3.2
show absorbance at 450 nm
[0158]
TABLE-US-00013
TABLE 8c
Relative Percent Distribution of Carotenoids
in Petals of Tagetes erecta and Mutant Crosses
Wave-
length in Marigold Selections
Carotenoid EtOH (nm) `Scarletade` 124-257 101-190 27774-008 27774-050
27774-064 27774-076 27774-123
Phytoene 216, 286, 0.5 3.9 3.9 4.4 5.2 7.0 8.8 5.6
(isomers) 297
Phytofluene 331, 348, 0.7 3.6 4.6 4.6 5.7 6.0 8.8 5.5
(isomers) 367
.zeta.-Carotene 377, 399, <0.2 3.3 5.1 4.2 8.5 6.0 9.8 5.9
(cis/trans 425
isomers)
Neurosporene 416, 440, <0.2 <0.2 <0.2 0.2 <0.2 0.3 0.3 <0.2
470
Lycopene 447, 472, <0.2 0.5 <0.2 0.4 0.6 0.4 1.5 0.2
504
.alpha.-Carotene 423, 444, <0.2 <0.2 0.3 <0.2 <0.2 <0.2
<0.2 <0.2
473
.beta.-Carotene 425, 451, <0.2 7.4 1.6 7.0 9.5 5.8 9.9 10.1
478
Neoxanthin 415, 439, 0.5 3.4 <0.2 <0.2 <0.2 <0.2 <0.2
<0.2
467
Violaxanthin 419, 440, 0.7 12.7 <0.2 <0.2 <0.2 <0.2 <0.2
<0.2
470
Antheraxanthin 422, 444, 1.6 17.5 0.6 2.5 <0.2 1.5 1.9 2.5
472
Lutein 420, 445, 91.0 2.3 63.8 0.8 0.8 0.7 0.6 0.8
475
Zeaxanthin 428, 450, 3.3 29.8 16.8 71.2 66.9 67.8 54.3 64.3
478
.alpha.-Cryptoxanthin 421, 446, <0.2 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2 <0.2
475
.delta.-Carotene 431, 456, <0.2 <0.2 0.2 <0.2 <0.2 <0.2
<0.2 <0.2
489
.beta.-Cryptoxanthin 428, 450, <0.2 1.0 0.2 1.1 1.0 1.6 1.3 1.3
478
.beta.-Zeacarotene 406, 428, not identified
454
Chrysanthemaxanthin 400, 421, <0.2 1.7 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2
448
Flavoxanthin 400, 421,
448
Auroxanthin 380, 401, not identified
426
Other compounds that 1.7 12.9 2.8 3.6 1.3 2.9 2.4 3.4
show absorbance at 450 nm
[0159]
TABLE-US-00014
TABLE 9a
Relative Percent Distribution of Carotenoids in
Leaves of Tagetes erecta and Mutant Crosses
Wave-
length
in EtOH Marigold Selections
Carotenoid (nm) `Scarletade` 124-257 100-198 27772-029 27772-036 27772-100
27772-109 27772-123 27772-130 27772-134
Phytoene 276, 286, Inadequate Peak Separation
297
Neoxanthin 415, 439, 9.4 9.6 0.3 <0.2 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2
467
Violaxanthin 419, 440, 7.1 26.3 0.4 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2 <0.2
470
Antheraxanthin 422, 444, 1.1 7.7 2.6 1.7 1.8 3.1 3.4 2.5 2.2 1.5
472
Lutein 420, 445, 44.7 0.4 34.8 <0.2 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2
475
Zeaxanthin 428, 450, 0.3 4.8 29.6 59.1 59.9 59.0 61.4 60.4 61.1 67.0
478
.beta.-Carotene 425, 451, 26.9 37.9 22.1 29.0 28.4 28.5 28.0 29.6 28.2
24.3
478
.alpha.-Carotene 423, 444, 0.8 <0.2 0.3 <0.2 <0.2 <0.2 <0.2
1.1 <0.2 <0.2
473
Chrysanthema- 400, 421, 0.7 1.5 <0.2 <0.2 0.6 0.4 <0.2 <0.2
<0.2 <0.2
xanthin 448
Flavoxanthin 400, 421,
448
.beta.-Cryptoxanthin 428, 450, 0.2 0.3 0.5 <0.2 0.6 <0.2 0.5 <0.2
<0.2 0.4
478
Other compounds that 8.8 11.5 9.4 10.2 8.7 9.0 6.8 6.4 8.6 6.9
show absorbance at 450 nm
[0160]
TABLE-US-00015
TABLE 9b
Relative Percent Distribution of Carotenoids in
Leaves of Tagetes erecta and Mutant Crosses
Wave-
length
in EtOH Marigold Selections
Carotenoid (nm) `Scarletade` 124-257 101-190 27773-006 27773-030 27773-087
27773-107 27773-128
Phytoene 276, 286, Inadequate Peak Separation
297
Neoxanthin 415, 439, 9.4 9.6 7.6 6.2 5.0 4.6 3.7 6.9
467
Violaxanthin 419, 440, 7.1 26.3 3.9 2.9 1.8 1.7 0.9 4.7
470
Antharaxanthin 422, 444, 1.1 7.7 7.9 8.7 8.1 6.6 6.6 13.9
472
Lutein 420, 445, 44.7 0.4 37.6 0.9 0.4 <0.2 0.4 0.7
475
Zeaxanthin 428, 450, 0.3 4.8 9.2 43.2 44.9 47.8 48.5 30.3
478
.beta.-Carotene 425, 451, 26.9 37.9 25.2 30.9 32.3 31.8 31.6 32.2
478
.alpha.-Carotene 423, 444, 0.8 <0.2 0.5 <0.2 <0.2 <0.2 <0.2
<0.2
473
Chrysanthemaxanthin 400, 421, 0.7 1.5 <0.2 <0.2 <0.2 <0.2
<0.2 0.5
448
Flavoxanthin 400, 421,
448
.beta.-Cryptoxanthin 428, 450, 0.2 0.3 <0.2 <0.2 <0.2 <0.2
<0.2 0.7
478
Other compounds that 8.8 11.5 8.1 7.3 7.6 7.5 6.3 10.2
show absorbance at 450 nm
[0161]
TABLE-US-00016
TABLE 9c
Relative Percent Distribution of Carotenoids in Leaves of Tagetes erecta
and Mutant Crosses
Wave-
length
in EtOH Marigold Selections
Carotenoid (nm) `Scarletade` 124-257 101-190 27774-008 27774-050 27774-064
27774-076 27774-123
Phytoene 276, 286, Inadequate Peak Separation
297
Neoxanthin 415, 439, 9.4 9.6 7.6 4.7 5.7 4.7 5.2 6.2
467
Violaxanthin 419, 440, 7.1 26.3 3.9 1.4 2.9 1.6 1.7 3.3
470
Antheraxanthin 422, 444, 1.1 7.7 7.9 7.4 11.4 7.2 7.8 11.7
472
Lutein 420, 445, 44.7 0.4 37.6 1.2 0.5 0.5 0.4 0.8
475
Zeaxanthin 428, 450, 0.3 4.8 9.2 48.2 41.5 49.0 48.3 40.5
478
.beta.-Carotene 425, 451, 26.9 37.9 25.2 27.5 29.9 27.4 28.4 27.2
478
.alpha.-Carotene 423, 444, 0.8 <0.2 0.5 1.1 <0.2 <0.2 <0.2
<0.2
473
Chrysanthemaxanthin 400, 421, 0.7 1.5 <0.2 0.5 0.4 0.5 <0.2 0.3
448
Flavoxanthin 400, 421,
448
.beta.-Cryptoxanthin 428, 450, 0.2 0.3 <0.2 <0.2 0.5 <0.2 <0.2
0.5
478
Other compounds that 8.8 11.5 8.1 8.0 7.3 9.2 8.3 9.5
show absorbance at 450 nm
[0162]
TABLE-US-00017
TABLE 10
Relative Percent Non-esterified Zeaxanthin In
Petals of Tagetes erecta And Mutant Crosses
% Non-esterifed
Marigold Selection Zeaxanthin
`Scarletade` 0
124-257 1.1
100-198 2.2
101-190 1.6
27772-029 6.8
27772-036 5.8
27772-100 7.9
27772-109 13.0
27772-123 7.3
27772-130 6.4
27772-134 5.0
27773-006 8.1
27773-030 3.2
27773-087 13.6
27773-107 19.3
27773-128 7.4
27774-008 3.9
27774-050 9.1
27774-064 6.3
27774-076 4.5
27774-123 6.8
[0163] Mutant selection 119-494 (Table 6a), characterized as having an
increased zeaxanthin to lutein ratio compared to wild type, was selfed
and the resulting seed was maintained. Mutant selection 115-004 (Table
6c), characterized as having an increased phytoene to lutein ratio
compared to wild type, was selfed and the resulting seed was maintained.
[0164] The selfed selection 115-004 was used as a female parent in a cross
with male parent selfed 119-494. From this cross, F.sub.1 plants were
produced and selfed to yield an F.sub.2 population. F.sub.2 plants
exhibiting increased lycopene isomer accumulation as compared to wild
type Tagetes erecta were noted by their red color in a greenhouse
planting. Analysis confirmed the lycopene accumulation as well as
increased levels of phytoene and .beta.-carotene. Samples were analyzed
according to the HPLC protocol outlined above with the exception that a
second hexane extraction was not performed. Data from six selections
denominated 33457-1, 33458-1, 33459-1, 33456-2, 33458-2 and 33461-1 are
reported in Table 11, below.
[0165] Additional lycopene, phytoene and .beta.-carotene accumulators were
subsequently noted. Selection 27774-105 was from the cross of female
parent 14649-3 and male parent 101-190 (Table 8b) described in this
Example. Petals were analyzed as described above and data are reported in
Table 11.
[0166] Selection 23012-3 is an F.sub.3 plant resulting from the cross of a
large-double flower PanAmerican Seed proprietary breeding line 85394-2 as
the female parent and 124-257 as the male parent. After selfing, an
F.sub.2 selection characterized as having reduced lutein level was
identified by the TLC procedure and the resulting F.sub.3 seed was sown
in the field located at PanAmerican Seed Santa Paula, Calif. In this
population selection 23012-3 was identified by its red colored petals.
Petals were analyzed as described above and data are reported in Table
11.
TABLE-US-00018
TABLE 11
Relative Percent Distribution of Carotenoids In Petals of Tagetes erecta
And Mutants
Wave-
length
in EtOH Marigold Selections
Carotenoid (nm) `Scarletade` 124-257 33457-1 33458-1 33459-1 33456-2
33458-2 33461-1 23012-3 27774-105
Phytoene 276, 286, 0.5 3.9 25.7 15.9 24.7 16.8 17.0 14.9 10.5 8.6
(isomers) 297
Phytofluene 331, 348, 0.7 3.6 15.4 8.6 14.3 13.6 13.1 11.4 5.8 8.4
(isomers) 367
.zeta.-Carotene 377, 399, <0.2 3.3 10.0 5.4 10.4 10.2 10.6 8.4 6.3 4.0
(cis/trans 425
isomers)
Neurosporene 416, 440, <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2 <0.2 <0.2
470
Lycopene 447, 472, <0.2 0.5 3.5 3.2 3.9 5.6 6.3 8.5 13.6 6.8
504
.alpha.-Carotene 423, 444, <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2 <0.2 <0.2
473
.beta.-Carotene 425, 451, <0.2 7.4 3.8 3.8 3.8 16.1 12.4 9.8 9.9 10.5
478
Neoxanthin 415, 439, 0.5 3.4 2.0 3.0 3.3 3.1 2.9 4.1 1.3 1.2
467
Violaxanthin 419, 440, 0.7 12.7 4.4 9.6 4.4 4.0 4.7 5.4 5.9 4.0
470
Antheraxanthin 422, 444, 1.6 17.5 6.7 13.7 5.7 5.6 6.2 6.7 10.4 11.3
472
Lutein 420, 445, 91.0 2.3 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
2.1 1.7
475
Zeaxanthin 428, 450, 3.3 29.8 14.9 23.0 10.2 11.9 12.8 18.0 18.5 32.0
478
.alpha.-Cryptoxanthin 421, 446, <0.2 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2 <0.2 <0.2 <0.2
475
.delta.-Carotene 431, 456, <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
<0.2 <0.2 <0.2 <0.2
489
.beta.-Cryptoxanthin 428, 450, <0.2 1.0 0.5 0.7 0.4 0.5 0.5 0.5 0.6 1.1
478
.beta.-Zeacarotene 406, 428, not identified
454
Chrysanthemaxanthin 400, 421, <0.2 1.7 1.1 1.9 1.0 0.8 0.9 0.7 1.7 1.0
448
Flavoxanthin 400, 421,
448
Auroxanthin 380, 401, not identified
426
Other compounds that 1.7 12.9 12.1 11.2 17.9 11.7 12.8 11.7 13.3 9.4
show absorbance at 450 nm
*Certain peaks have not been characterized and a significant number of
those listed above as well as other peaks may be lycopene isomers.
EXAMPLE 8
Alternate Methods for Creating Altered Carotenoid Profiles in Tagetes
erecta
[0167] In addition to creating Tagetes erecta having altered carotenoid
profiles through the use of chemical mutagenesis, alternative methods for
providing an altered carotenoid profile can be utilized. Illustrative
alternate methods include the use of ionizing radiation and gene
silencing using recombinant DNA technology.
[0168] More specifically, ionizing radiation has been used to modify gene
expression through deletion mutations. Gamma rays have been reported to
modify flower color in ornamental species including Dendranthema,
Gladiolus and Zinnia [See Datta et al., Zeitschrift fur Pflanzen.,
120(1):91-92 (2001); Masakazu, et al., J. Japanese Soc. For Hort. Sci.,
70(1):126-128 (2001) and Venkatachalam et al., Ind. Jour. Gen. & Plant
Breed., 57(3):2S5-261 (1997)]. Fast neutrons have been effective in
generating deletion mutations in plants. Thus, deletion mutants were
obtained for 84% of targeted loci from a mutated Arabidopsis population
of 51,840 plants [See Li et al., The Plant Journal,
27(3):235-242(2001).], whereas Love et al., Amer. Soc. Hort. Sci.,
8B:627-630 (1966) prepared foliage anthocyanin mutations in Coleus. More
recently, flower color mutants of Dahlia were reported [See Abe et al.,
In Vitro Cell. & Dev. Bio. 38:93A (2002)].
[0169] Gene silencing can also be used to inactivate targeted genes in
order to prepare desirable phenotypes such as altered flower pigmentation
profiles. Such methods include gene silencing at the transcriptional as
well as posttranscriptional level.
[0170] Recombinantly-induced, stably integrated transgenes as well as
replicating DNA and RNA viruses can mediate silencing events.
Transcriptional gene silencing results from the impairment of
transcription initiation through promoter methylation and/or chromatin
condensation. Homozygous progeny of transgenic petunia containing a
transgene for brick-red pelargonidin flower pigmentation unexpectedly
yielded a white derivative having a hypermethylated CaMV 35S promoter
[See Meyer et al., Plant Journal 4(1):89-100 (1993)].
[0171] Post-transcriptional gene silencing, in which transcription occurs
but RNA fails to accumulate, results from the degradation of mRNA when
aberrant sense, antisense, or double-stranded forms of RNA are produced.
In petunia, a recombinantly-introduced, transcribed sense transgene
encoding for the enzyme chalcone synthase of the flavonoid biosynthetic
pathway could down-regulate the expression of homologous endogenous gene
and transgene RNA, a phenomenon termed co-suppression. Instead of the
expected increased production of the encoded enzyme, 42 percent of the
transgenic plants had flowers that were white and/or patterned with white
[See Napoli et al., Plant Cell, 2 (4):279-289 (1990)].
[0172] Before the discovery of co-suppression, down-regulation of
endogenous genes was achieved with antisense transgenes. A comparison of
sense and antisense chalcone synthase transgenic Petunia identified 75%
of the sense transgenics and 82% of the antisense transgenics as having
altered flower pigmentation [See Jorgensen et al., Plant Mol. Biol.,
31(5):957-973 (1996)].
[0173] From double-stranded RNA, small interfering RNAs (siRNA) are
processed, and these have been shown to be effective in silencing genes
in plants [See Hamilton et al., Science, 286(5441):950-952 (1999)].
Intermediates of RNA degradation were identified in co-suppressed petunia
plants [See Metzlaff et al., Cell 88(6):845-854 (1997)]. Transformation
vectors that produced RNAs capable of duplex formation caused specific
and heritable genetic interference of four flower- or meristem-related
genes in Arabidopsis thaliana [See Chuang et al., Proc. Natl. Acad. Sci.,
97(9):4985-4990 (2000)].
[0174] In addition, post-transcriptional gene silencing can be
accomplished through vectors engineered to express ribozymes capable of
cleaving RNA. One class termed `small ribozymes` includes hairpin
ribozyme and hammerhead ribozyme. Efficient gene silencing was also
demonstrated in a wide range of plant species using constructs encoding
self-complementary hairpin RNA. Intron-containing constructs generally
resulted in 90 to 100% of independent transgenics showing gene silencing
[See Wesley et al., Plant Journal, 27(6):581-590 (2001)]. A transgenic
potato plant expressing a hammerhead ribozyme directed against the potato
spindle tuber viroid RNA showed high resistance against its replication.
This resistance was stably inherited to progeny [See Yang et al., Proc.
Natl. Acad. Sci., 94:4861-4865 (1997)].
[0175] In the present invention, suitable recombinantly-provided
transgenes for gene silencing include expression vectors containing one
or more sequence(s) of a Tagetes plant encoding enzyme(s) necessary for
carotenoid production. Methods of introducing expression vectors into
plant tissue include direct gene transfer method such as
microprojectile-mediated delivery, DNA injection, electroporation, and
the like [See Gruber et al., infra; Miki et al., in Methods in Plant
Molecular Biology and Biotechnology, Glick et al. eds., CRC Press, Boca
Raton, Fla., pages 67-88 (1993); Klein et al., Biotechnology 10:268
(1992)]. Expression vectors are also introduced into plant tissues via
direct infection or co-cultivation of plant tissue with Agrobacterium
tumefaciens [See Horsch et al., Science 227:1229 (1985)]. Descriptions of
Agrobacterium vector systems and methods for Agrobacterium-mediated gene
transfer are provided by Gruber et al., "Vectors for Plant
Transformation," in Methods in Plant Molecular Biology and Biotechnology,
Glick et al. (eds.), pages 89-119 (CRC Press, 1993), Miki et al., supra,
and Moloney et al., Plant Cell Reports 8:238 (1989).
[0176] Each of the patents and articles cited herein is incorporated by
reference. The use of the article "a" or "an" is intended to include one
or more.
[0177] The foregoing description and the examples are intended as
illustrative and are not to be taken as limiting. Still other variations
within the spirit and scope of this invention are possible and will
readily present themselves to those skilled in the art.
* * * * *