Leucocyanidin reductase activity and accumulation of proanthocyanidins in developing legume tissues

Skadhauge, Birgitte; Gruber, Margaret Y.; Thomsen, Kristine Rømer; Wettstein, Diter von

doi:10.2307/2446026

Cited by 45 publications

(46 citation statements)

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“…This pattern of pigment deposition is similar to that observed by Skadhauge et al (1997) in immature seed coats of alfalfa stained with vanillin. Vanillin staining revealed a strong reduction of PA deposition in the vacuoles of tt12 endothelial cells.…”

Section: Pa Deposition In Vacuoles Of the Endothelium Is Disturbed Insupporting

confidence: 85%

The TRANSPARENT TESTA12 Gene of Arabidopsis Encodes a Multidrug Secondary Transporter-like Protein Required for Flavonoid Sequestration in Vacuoles of the Seed Coat Endothelium

et al. 2001

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Phenolic compounds that are present in the testa interfere with the physiology of seed dormancy and germination. We isolated a recessive Arabidopsis mutant with pale brown seeds, transparent testa12 ( tt12 ), from a reduced seed dormancy screen. Microscopic analysis of tt12 developing and mature testas revealed a strong reduction of proanthocyanidin deposition in vacuoles of endothelial cells. Double mutants with tt12 and other testa pigmentation mutants were constructed, and their phenotypes confirmed that tt12 was affected at the level of the flavonoid biosynthetic pathway. The TT12 gene was cloned and found to encode a protein with similarity to prokaryotic and eukaryotic secondary transporters with 12 transmembrane segments, belonging to the MATE (multidrug and toxic compound extrusion) family. TT12 is expressed specifically in ovules and developing seeds. In situ hybridization localized its transcript in the endothelium layer, as expected from the effect of the tt12 mutation on testa flavonoid pigmentation. The phenotype of the mutant and the nature of the gene suggest that TT12 may control the vacuolar sequestration of flavonoids in the seed coat endothelium. INTRODUCTIONFlavonoids represent a highly diverse group of plant aromatic secondary metabolites. The major forms, which are anthocyanins (red to purple pigments), flavonols (colorless to pale yellow pigments), and proanthocyanidins (PAs), also known as condensed tannins (colorless pigments that brown with oxidation), are present in proportions and amounts that vary according to the plant species, the organ, the stage of development, and environmental growth conditions. Arabidopsis contains flavonoid pigments in vegetative tissues and in seeds (Shirley et al., 1995). In the mature testa, flavonoids were detected in both the endothelium and the three crushed parenchymal layers just above the endothelium . PAs have been shown to accumulate exclusively in the endothelium layer (Devic et al., 1999). Wild-type seed color depends on the stage of development: as long as the testa is transparent, until ‫ف‬ 10 days after pollination, the seed has the color of the underlying endosperm and embryo. At maturity, the testa becomes opaque after the oxidation of flavonoid pigments, which gives the seed its characteristic brown color. Therefore, the color of mutants with seed flavonoid defects ranges from pale yellow (complete lack of visible pigments in the testa) to pale brown, depending on the accumulated intermediate flavonoids .In Arabidopsis, mutants at 21 loci have been isolated on the basis of altered testa pigmentation (Figure 1). The genes disrupted in the transparent testa ( tt ) mutants tt3 , tt4 , tt5 , tt6 , and tt7 (Shirley et al., 1995) and the banyuls ( ban ) mutant (Albert et al., 1997) code for the enzymes dihydroflavonol-4-reductase (Shirley et al., 1992), chalcone synthase (Feinbaum and Ausubel, 1988), chalcone isomerase (Shirley et al., 1992), flavonol 3-hydroxylase (Pelletier and Shirley, 1996; Wisman et al., 1998), flavonol 3 Ј -hydroxylase (Ko...

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Section: Pa Deposition In Vacuoles Of the Endothelium Is Disturbed Insupporting

confidence: 85%

The TRANSPARENT TESTA12 Gene of Arabidopsis Encodes a Multidrug Secondary Transporter-like Protein Required for Flavonoid Sequestration in Vacuoles of the Seed Coat Endothelium

et al. 2001

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“…The first committed step to PA biosynthesis, and the only one to be enzymically characterized, is catalyzed by the enzyme leucoanthocyanidin reductase (LAR). Reactions catalyzing the conversion of (ϩ)-3,4-cis-leucocyanidin to (ϩ)- gumes (Stafford and Lester, 1984;Tanner and Kristiansen, 1993;Singh et al, 1997;Skadhauge et al, 1997). PA is thought to be synthesized by sequential addition of an intermediate derived from a flavan-3,4-diol (e.g.…”

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confidence: 99%

Identification and Biochemical Characterization of Mutants in the Proanthocyanidin Pathway in Arabidopsis

et al. 2002

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Proanthocyanidin (PA), or condensed tannin, is a polymeric flavanol that accumulates in a number of tissues in a wide variety of plants. In Arabidopsis, we found that PA precursors (detected histochemically using OsO 4 ) accumulate in the endothelial cell layer of the seed coat from the two-terminal cell stage of embryo development onwards. To understand how PA is made, we screened mature seed pools of T-DNA-tagged Arabidopsis lines to identify mutants defective in the synthesis of PA and found six tds (tannin-deficient seed) complementation groups defective in PA synthesis. Mutations in these loci disrupt the amount (tds1, tds2, tds3, tds5, and tds6) or location and amount of PA (tds4) in the endothelial cell layer. The PA intermediate epicatechin has been identified in wild type and mutants tds1, tds2, tds3, and tds5 (which do not produce PA) and tds6 (6% of wild-type PA), whereas tds4 (2% of wild-type PA) produces an unidentified dimethylaminocinnamaldehyde-reacting compound, indicating that the mutations may be acting on genes beyond leucoanthocyanidin reductase, the first enzymatic reduction step dedicated to PA synthesis. Two other mutants were identified, an allele of tt7, which has a spotted pattern of PA deposition and produces only 8% of the wild-type level of type PA as propelargonidin, and an allele of tt8 producing no PA. Spotted patterns of PA deposition observed in seed of mutants tds4 and tt7-3 result from altered PA composition and distribution in the cell. Our mutant screen, which was not exhaustive, suggests that the cooperation of many genes is required for successful PA accumulation.Flavonoids are a diverse group of plant secondary metabolites that accumulate in a wide variety of plant tissues and include anthocyanins, flavonols, and the polymeric flavanols known as proanthocyanidins (PAs; Fig. 1). Like their flavanol constituents, PAs are rich in hydrophobic aromatic rings and hydroxyl groups that can interact with biological molecules, particularly proteins, by hydrogen bonds and hydrophobic interactions. Because PAs are polymeric, their interaction with proteins is much stronger than that of monomeric flavanols, presumably because of a "chelate" effect where polymeric PAs can interact with large proteins at multiple sites, increasing the strength of overall molecular interaction as well as minimizing dissociation of the complex once it is formed (Fersht, 1985). This strong interaction of PAs with proteins is probably the basis of their main role in plants and their uses by man.Because PA content of dietary plants can have both positive and negative effects on animal nutrition (Waghorn and Jones, 1989), an important agricultural objective is to manipulate the level of PA in pasture legumes (Morris and Robbins, 1997). When present in bloat-safe forage legumes, PA can bind to and cause the precipitation of dietary proteins, inhibiting the formation of stable proteinaceous foams, thereby preventing bloat (Tanner et al., 1995). Increasing the PA content of pastures such as alfalfa (Medicago s...

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“…Relationships between traits were calculated using the Correlation Coefficient module in Microsoft Excel Data Analysis ToolPak. Histochemical staining of PA by butanol:HCl hydrolysis was evaluated by light microscopy according to Skadhauge et al (1997). Two PA-accumulating tan1 and tan2 mutants were selected for analysis from a Tn/T-DNA insertion population of L. c. var.…”

Section: Thirty-twomentioning

confidence: 99%

“…Flowers and seed coats of L. c. var. japonicus ecotype Gifu B129 have been shown to produce moderate to high levels of PA (Skadhauge et al 1997), but polymer size and flavonoid composition have not been reported for this species. Stem anthocyanin levels have been correlated with habitat latitude for 66 wild-grown accessions of L. c. var.…”

mentioning

confidence: 94%

“…L. pedunculatus) and tetraploid birdsfoot (deervetch) trefoil (L. corniculatus L.) (Beuselinck and Grant 1995;Wedderburn and Gwynne 1981). These forages accumulated substantial levels of PA in leaf, flower, and seed coat, and small to moderate amounts in other tissues (Lees 1994;Skadhauge et al 1997). A strong relationship has been established between forage quality and PA composition in L. c. var.…”

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confidence: 99%

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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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Leucocyanidin reductase activity and accumulation of proanthocyanidins in developing legume tissues

Cited by 45 publications

References 35 publications

The TRANSPARENT TESTA12 Gene of Arabidopsis Encodes a Multidrug Secondary Transporter-like Protein Required for Flavonoid Sequestration in Vacuoles of the Seed Coat Endothelium

The TRANSPARENT TESTA12 Gene of Arabidopsis Encodes a Multidrug Secondary Transporter-like Protein Required for Flavonoid Sequestration in Vacuoles of the Seed Coat Endothelium

Identification and Biochemical Characterization of Mutants in the Proanthocyanidin Pathway in Arabidopsis

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

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