			Home About us Contact

Anthocyanin Biosynthesis (anthocyanin + biosynthesis)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

Plastid signals that affect photomorphogenesis in Arabidopsis thaliana are dependent on GENOMES UNCOUPLED 1 and cryptochrome 1

NEW PHYTOLOGIST, Issue 2 2009
Michael E. Ruckle
Summary ,,When plastids experience dysfunction they emit signals that help coordinate nuclear gene expression with their functional state. One of these signals can remodel a light-signaling network that regulates the expression of nuclear genes that encode particular antenna proteins of photosystem II. These findings led us to test whether plastid signals might impact other light-regulated processes. ,,Photomorphogenesis was monitored in genomes uncoupled 1 (gun1), cryptochrome 1 (cry1), and long hypocotyl 5 (hy5), which have defects in light and plastid signaling, by growing Arabidopsis thaliana seedlings under various light conditions and either treating or not treating them with antibiotics that induce chloroplast dysfunction and trigger plastid signaling. ,,It was found that plastid signals that depend on GUN1 can affect cotyledon opening and expansion, anthocyanin biosynthesis, and hypocotyl elongation. We also found that plastid signals that depend on CRY1 can regulate cotyledon expansion and development. ,,Our findings suggest that plastid signals triggered by plastid dysfunction can broadly affect photomorphogenesis and that plastid and light signaling can promote or antagonize each other, depending on the responses studied. These data suggest that GUN1 and cry 1 help to integrate chloroplast function with photomorphogenesis. [source]

Exogenous ethylene stimulates the long-term expression of genes related to anthocyanin biosynthesis in grape berries

PHYSIOLOGIA PLANTARUM, Issue 2 2003
Ashraf El-Kereamy
The treatment of grape berries (Vitis vinifera L. cv. Cabernet Sauvignon) with the ethylene-releasing compound, 2-chloroethylphosphonic acid (2-CEPA), at veraison is a method known to enhance grape skin colour. We observed that it produced a 6-fold increase, up to 30 pmol g,1 FW, of the cluster internal ethylene compared to untreated controls within the 24 h following treatment. This ethylene upsurge was associated with increased levels of chalcone synthase (CHS) and flavanone 3-hydroxylase (F3H) transcripts, which persisted over the following 20 days. Transcript levels of leucoanthocyanidin dioxygenase (LDOX) and UDP glucose-flavonoid 3- O -glucosyl transferase (UFGT) were similarly enhanced by 2-CEPA, although to a lesser extent. The effect on UFGT was confirmed at the protein level by an immunoblot analysis. The transcript accumulation of dihydroflavonol 4-reductase (DFR) was unaffected by 2-CEPA treatment. Examination of the levels of CHS, F3H and UFGT mRNAs in berries during bunch exposure to ethylene, revealed elevated levels of each transcript within the first 6 h of treatment when compared to nonethylene-treated controls. HPLC analyses of berry skin extracts showed that levels of each of the anthocyanins analysed (delphinidin, cyanidin, petunidin, peonidin and malvidin) increased over the 10 days following the ethylene burst, and decreased thereafter. However, anthocyanin levels at harvest were still higher in ethylene treated grapes than in controls. This data is the first evidence that ethylene triggers gene expression related to anthocyanin synthesis in grapes, and in addition, our results also confirm the existence of other regulatory modes in the anthocyanin biosynthetic pathway. [source]

Engineered native pathways for high kaempferol and caffeoylquinate production in potato

PLANT BIOTECHNOLOGY JOURNAL, Issue 9 2008
Caius M. Rommens
Summary Flavonols and caffeoylquinates represent important groups of phenolic antioxidants with health-promoting activities. The genetic potential of potato (Solanum tuberosum) to produce high levels of these dietary compounds has not been realized in currently available commodity varieties. In this article, it is demonstrated that tuber-specific expression of the native and slightly modified MYB transcription factor gene StMtf1M activates the phenylpropanoid biosynthetic pathway. Compared with untransformed controls, transgenic tubers contained fourfold increased levels of caffeoylquinates, including chlorogenic acid (CGA) (1.80 mg/g dry weight), whilst also accumulating various flavonols and anthocyanins. Subsequent impairment of anthocyanin biosynthesis through silencing of the flavonoid-3,,5,-hydroxylase (F3,5,h) gene resulted in the accumulation of kaempferol-rut (KAR) to levels that were approximately 100-fold higher than in controls (0.12 mg/g dry weight). The biochemical changes were associated with increased expression of both the CGA biosynthetic hydroxycinnamoyl-CoA quinate hydroxycinnamoyl transferase (Hqt) gene and the upstream chorismate mutase (Cm) and prephenate dehydratase (Pdh) genes. Field trials indicated that transgenic lines produced similar tuber yields to the original potato variety Bintje. Processed products of these lines retained most of their phenylpropanoids and were indistinguishable from untransformed controls in texture and taste. [source]

FUSCA3 from barley unveils a common transcriptional regulation of seed-specific genes between cereals and Arabidopsis

THE PLANT JOURNAL, Issue 6 2008
Miguel Ángel Moreno-Risueno
Summary Accumulation of storage compounds in the embryo and endosperm of developing seeds is a highly regulated process that allows seedling growth upon germination until photosynthetic capacity is acquired. A critical regulatory element in the promoters of seed storage protein (SSP) genes from dicotyledonous species is the RY box, a target of B3-type transcription factors. However, the functionality of this motif in the transcriptional regulation of SSP genes from cereals has not been fully established. We report here the identification and molecular characterization of barley FUSCA3, a B3-type transcription factor as yet uncharacterized in monocotyledonous plants. Our results show that both the barley and Arabidopsis FUS3 genes maintain a conserved functionality for the regulation of SSP genes and anthocyanin biosynthesis in these two distantly related phylogenetic groups. Complementation of the loss-of-function mutant fus3 in Arabidopsis by the barley HvFus3 gene resulted in restored transcription from the At2S3 gene promoter and normal accumulation of anthocyanins in the seed. In barley, HvFUS3 participates in transcriptional activation of the endosperm-specific genes Hor2 and Itr1. HvFUS3, which specifically binds to RY boxes in EMSA experiments, trans -activates Hor2 and Itr1 promoters containing intact RY boxes in transient expression assays in developing endosperms. Mutations in the RY boxes abolished the HvFUS3-mediated trans -activation. HvFus3 transcripts accumulate in the endosperm and in the embryo of developing seeds, peaking at mid maturation phase. Remarkably, HvFUS3 interacts with the Opaque2-like bZIP factor BLZ2 in yeast, and this interaction is essential for full trans -activation of the seed-specific genes in planta. [source]