On the Site of Tannin Synthesis in Plant Cells

Parham, Russell A.; Kaustinen, Hilkka M.

doi:10.1086/336950

Cited by 77 publications

(28 citation statements)

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“…The occurrence of PA in small vacuoles in tds4 is unlikely to be due to the low level of PA produced in this mutant because tds6, which accumulates a similar low level of PA, does not form a patchy pattern of PA when stained with DMACA. It is intriguing to note that PA-containing provacuoles that undergo fusion with the main vacuole have been reported (Chafe and Durzan, 1973;Baur and Walkinshaw, 1974;Parham and Kaustinen, 1977;Hilling and Amelunxen, 1985). These results suggest that the pathway of PA accumulation may be much more complex than a minimal pathway that involves membranebound transporters transporting monomeric units into a preexisting vacuole.…”

Section: Discussionmentioning

confidence: 96%

“…A single transporter could facilitate transport of all monomers of PA synthesis, but multiple specific transporters that discriminate between initiator and extender units, 2,3-cis and 2Ј3-trans isomers, and the B-ring hydroxylation isomers would give more control over the composition and M r of the final PA polymer. Although the vacuole is the ultimate site of PA accumulation in the cell, PA-containing provacuoles have been observed to originate from the rough endoplasmic reticulum (Chafe and Durzan, 1973;Baur and Walkinshaw, 1974;Parham and Kaustinen, 1977). These small provacuoles appear to undergo fusion with a larger vacuole in the cell.…”

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confidence: 99%

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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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Section: Discussionmentioning

confidence: 96%

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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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“…In P. tomentosa (stock) and P. armeniaca (scion), a differential accumulation of flavon-3-ols occurring during the early stages of grafting was related to problems in the differentiation of callus (Errea et al, 1994;Salvatierra et al, 1999) and cathechin, a flavonol, is known to be a protective agent against IAA oxidation (Lee and Oda, 2003;Parham and Kaustinen, 1977;Salvatierra et al, 1999) and can modulate the IAA oxidase level (Salvatierra et al, 1999). Moreover, the synthesis of prunasin, another flavon-3-ol, can determine incompatibility in Prunus (Moing and Carde, 1988;Stafford, 1990) and be stimulated by ABA and GA Salvatierra et al, 1999;Aloni et al, 2010).…”

Section: The Role Of Hormonesmentioning

confidence: 99%

Graft incompatibility in plants: Metabolic changes during formation and establishment of the rootstock/scion union with emphasis on Prunus species

Gainza¹,

Opazo²,

Muñoz

2015

Chilean J. Agric. Res.

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Commercial fruit trees are usually formed by the combination of a rootstock and a scion to broaden the adaptability of scion cultivars to soil and climatic conditions, facilitate agricultural management, and/or increase productivity. In the different cultivated species of the genus Prunus, rootstocks having a wide range of uses are scarce, because of rootstock/ scion graft incompatibilities that prevent the establishment of a strong and lasting functional union. Graft incompatibility is a problem in cherry, almond, and apricot than in peach or plum. In general, closely related cultivars and species tend to be compatible, but taxonomically distant plants often manifest incompatibility. This review will focus on the knowledge currently available on the metabolic response during the formation and establishment of the stock/scion graft union in order to help the effort for identify future metabolic markers to be used in breeding programs. The physiological, metabolic and molecular mechanisms that cause incompatibility remain unclear and several hypotheses have been proposed to explain it, mostly based on herbaceous species. Few studies are available to explain incompatibility in woody plants. Various phenolic compounds are known to affect cell division, development and differentiation at the graft union. Flavonol (catechins and proanthocyanidins) concentrations increase shortly after grafting and, as a result of the stress induced during the healing response, vacuolar membrane disruption occurs resulting in the escape of phenols from the vacuole into the cytoplasmic matrix, causing dysfunctions in the growth of certain tissues (xylem and phloem), interference with the synthesis of lignin or inducing hormonal imbalances. All these abnormalities result in mechanical weakening of the union, which may manifest during the first year after grafting (translocated incompatibility) or may appear several years later (localized incompatibility), leading to major economic losses. More research is needed to fully understand the mechanism of graft incompatibility, particularly in woody plants. This knowledge is essential to develop molecular markers useful in rootstock breeding programs.

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“…The fact that PAs have been reported to reach the vacuole in vesicles derived from the endoplasmic reticulum (Baur and Walkinshaw, 1974;Parham and Kaustinen, 1977; Zobel, 1986;Ibrahim, 1992) is puzzling. It is possible that these vesicles bring PA precursors to the surface of the tonoplast, where they are handled by a transporter.…”

Section: The Tt12 Gene May Be Involved In Vacuolar Transport Of Flavomentioning

confidence: 99%

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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On the Site of Tannin Synthesis in Plant Cells

Cited by 77 publications

References 7 publications

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

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

Graft incompatibility in plants: Metabolic changes during formation and establishment of the rootstock/scion union with emphasis on Prunus species

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

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