Occurrence of an unusual leucoanthocyanidin and absence of proanthocyanidins in sorghum leaves

Watterson, Julia J.; Butler, Larry G.

doi:10.1021/jf00115a011

Cited by 107 publications

(65 citation statements)

References 9 publications

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“…These compounds have absorption maxima of 564 nm. Relative accumulation of flavan-4-ols was estimated by spectral analysis following previously published method (Waterson and Butler 1983;Grotewold et al 1998). Briefly, pericarp and cob tissues were collected at 20 days after pollination and immediately frozen in liquid nitrogen.…”

Section: Methodsmentioning

confidence: 99%

Progressive Loss of DNA Methylation Releases Epigenetic Gene Silencing From a Tandemly Repeated Maize Myb Gene

Sekhon¹,

Chopra

2009

Genetics

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Maize pericarp color1 (p1) gene, which regulates phlobaphene biosynthesis in kernel pericarp and cob glumes, offers an excellent genetic system to study tissue-specific gene regulation. A multicopy p1 allele, P1-wr (white pericarp/red cob) is epigenetically regulated. Hypomethylation of P1-wr in the presence of Unstable factor for orange1 (Ufo1), leads to ectopic pigmentation of pericarp and other organs. The Ufo1-induced phenotypes show incomplete penetrance and poor expressivity: gain of pigmentation is observed only in a subset of plants carrying Ufo1 mutation, and the extent of pigmentation is highly variable. We show that Ufo1 induces progressive hypomethylation of P1-wr repeats over generations. After five generations of exposure to Ufo1, a 30-40% decrease in CG and CNG methylation was observed in an upstream enhancer and an intron region of P1-wr. Interestingly, such hypomethylation correlated with an increase in penetrance of the Ufo1-induced pigmentation phenotype from $27 to 61%. Expressivity of the Ufo1-induced phenotype also improved markedly as indicated by increased uniformity of pericarp pigmentation in the later generations. Furthermore, the poor expressivity of the Uo1 is associated with mosaic methylation patterns of the P1-wr upstream enhancer in individual cells and distinct P1-wr gene copies. Finally, comparison of methylation among different tissues indicated that Ufo1 induces rapid CG and CNG hypomethylation of P1-wr repeats during plant development. Together, these data indicate that the poor penetrance and expressivity of Ufo1-induced phenotypes is caused by mosaicism of methylation, and progressive mitotic hypomethylation leads to improved meiotic heritability of the mutant phenotype. In duplicated genomes like maize, loss of an epigenetic regulator may produce mosaic patterns due to redundancy of epigenetic regulators and their target sequences. We show here that multiple developmental cycles may be required for complete disruption of suppressed epigenetic states and appearance of heritable phenotypes.

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Section: Methodsmentioning

confidence: 99%

Progressive Loss of DNA Methylation Releases Epigenetic Gene Silencing From a Tandemly Repeated Maize Myb Gene

Sekhon¹,

Chopra

2009

Genetics

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“…A low concentration of 80% (w/v) MeOHextractable proanthocyanidin (approximately 0.06%-0.1% fresh weight) was selectively bound to PVPP and was detected in both transgenic genotypes after heating the PVPP-bound material in butanol:HCl (Table VI; Watterson and Butler, 1983). Trace amounts of 80% (w/v) MeOH-extractable proanthocyanidin (Ͻ0.0005% fresh weight) could also be detected in non-transformed A01 leaves.…”

Section: Influence Of Lc On Leucocyanidin Reductase (Lcr) Activity Anmentioning

confidence: 96%

“…Subsequently, plants grown for 32 or 48 h under continuous light were tested for proanthocyanidin using more sensitive heat-dependent PVPP:butanol: HCl assays after tissue fractionation into 80% (w/v) MeOH-extractable and unextractable fractions (Watterson and Butler, 1983). Extractable fractions from the 48-h samples were further partitioned into aqueous and ethyl acetate subfractions.…”

Section: Influence Of Lc On Leucocyanidin Reductase (Lcr) Activity Anmentioning

confidence: 99%

Expression of Anthocyanins and Proanthocyanidins after Transformation of Alfalfa with Maize Lc

et al. 2003

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Three anthocyanin regulatory genes of maize (Zea mays; Lc, B-Peru, and C1) were introduced into alfalfa (Medicago sativa) in a strategy designed to stimulate the flavonoid pathway and alter the composition of flavonoids produced in forage. Lc constructs included a full-length gene and a gene with a shortened 5Ј-untranslated region. Lc RNA was strongly expressed in Lc transgenic alfalfa foliage, but accumulation of red-purple anthocyanin was observed only under conditions of high light intensity or low temperature. These stress conditions induced chalcone synthase and flavanone 3-hydroxylase expression in Lc transgenic alfalfa foliage compared with non-transformed plants. Genotypes containing the Lc transgene construct with a full-length 5Ј-untranslated region responded more quickly to stress conditions and with a more extreme phenotype. High-performance liquid chromatography analysis of field-grown tissue indicated that flavone content was reduced in forage of the Lc transgenic plants. Leucocyanidin reductase, the enzyme that controls entry of metabolites into the proanthocyanidin pathway, was activated both in foliage and in developing seeds of the Lc transgenic alfalfa genotypes. Proanthocyanidin polymer was accumulated in the forage, but (ϩ)-catechin monomers were not detected. B-Peru transgenic and C1 transgenic populations displayed no visible phenotypic changes, although these transgenes were expressed at detectable levels. These results support the emerging picture of Lc transgene-specific patterns of expression in different recipient species. These results demonstrate that proanthocyanidin biosynthesis can be stimulated in alfalfa forage using an myc-like transgene, and they pave the way for the development of high quality, bloat-safe cultivars with ruminal protein bypass.The ability to manipulate flavonoid biosynthesis in crop plants is gaining rapidly in importance as new economically important uses are found in the areas of nutraceuticals, food quality, and feed quality. The introduction of proanthocyanidin (PA, a flavonoid polymer) into alfalfa (Medicago sativa) forage is particularly important to ruminant livestock producers. Proanthocyanidins eliminate pasture bloat, improve the efficiency of conversion of plant protein into animal protein (ruminal protein bypass), reduce greenhouse gases, reduce gastrointestinal parasites, and inhibit insect feeding (Waghorn, 1990; Neizen et al., 1995 Neizen et al., , 1998 Aerts et al., 1999; Muir et al., 1999; McMahon et al., 2000). Alfalfa forage (leaf and stem tissues) accumulate anthocyanins only at senescence or locally under some stress conditions such as insect feeding (Goplen et al., 1980). No known conditions induce proanthocyanidins in alfalfa forage, although they are structurally related to anthocyanins. However, these compounds do accumulate in seed coats (Koupai-Abyazani et al., 1993).Anthocyanins and proanthocyanidins share early and middle steps of the flavonoid biosynthetic pathway, including chalcone synthase (CHS), chalcone isomerase, flavan...

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“…Grant and a few accessioions collected or developed as cultivars or mutants by the Saskatoon and Carlsberg Research Centres were maintained in a greenhouse in Saskatoon. PA concentration was measured in leaves randomly collected from three to six pre-pod flowering plants of each accession (depending on seed availability) according to Watterson and Butler (1983). A sub-set of 26 accessions (six plants each) were also grown to maturity and observed for morphology, tissue colour, and plant habit.…”

Section: Thirty-twomentioning

confidence: 99%

“…Growth details and seed for these species from the Grant collection are not available through PGRC, due to poor viability and lack of seed production during growth for PA assays. Proanthocyanidin concentration is average of three to five replications (extractions) and measured relative to a standard curve of polymer isolated from mature sainfoin leaves using a PVPP-binding butanol:HCl assay (Watterson et al 1983). y PA polymer size is average of at least three replicate extractions.…”

Section: L M)mentioning

confidence: 99%

Variation in morphology, plant habit, proanthocyanidins, and flavonoids within a Lottus germplasm collection

Gruber¹,

Skadhauge²,

Yu³

et al. 2008

Can. J. Plant Sci.

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K. 2008. Variation in morphology, plant habit, proanthocyanidins, and flavonoids within a Lotus germplasm collection. Can. J. Plant Sci. 88: 121Á132. Lotus species collected from a range of geographical locations were evaluated for relationships between plant habit and size, leaf proanthocyanidin (PA) content, flower colour, stem colour, leaf colour, trichome density, and geographic origin. No relationships occurred between leaf PA concentration and morphological trait or collection site. Trichome coverage was moderately correlated with plant size (r 0(0.70). Several accessions, e.g., L. angustissimus L. and L. castellanis Boiss. & Reut., consisted of small, trichome-covered plants distinct from the large, glabrous plants typical of the model species L. corniculatus var. japonicus ecotype Gifu B129. These two morphology types were also represented among the tan mutants of Gifu B129. Due to the importance of trichomes and PA in plant defence, PA composition was compared between L. angustissimus and tan1 (both representing the small trichome-covered phenotype) and ecotype Gifu B129 and tan2 (both representing the large, glabrous phenotype). Both the tan1 and tan2 mutants accumulated substantial amounts of leaf PA similar in size to the small oligomers recovered from leaves of L. angustissimus. PA polymers were undetectable in Gifu B129 leaves, while floral PA extracts of this ecotype included a much larger PA polymer. Flavonoid composition in leaves of tan1 and L. angustissimus was complex, and differed from the simple profile in Gifu B129 leaves.

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Occurrence of an unusual leucoanthocyanidin and absence of proanthocyanidins in sorghum leaves

Cited by 107 publications

References 9 publications

Progressive Loss of DNA Methylation Releases Epigenetic Gene Silencing From a Tandemly Repeated Maize Myb Gene

Progressive Loss of DNA Methylation Releases Epigenetic Gene Silencing From a Tandemly Repeated Maize Myb Gene

Expression of Anthocyanins and Proanthocyanidins after Transformation of Alfalfa with Maize Lc

Variation in morphology, plant habit, proanthocyanidins, and flavonoids within a Lottus germplasm collection

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