title: Transcriptional regulation of anthocyanin biosynthesis in ripening fruits of grapevine under seasonal water deficit.
abstract: Anthocyanin biosynthesis is strongly up-regulated in ripening fruit of grapevines (Vitis vinifera L.) grown under drought conditions. We investigated the effects of long-term water deficit on the expression of genes coding for flavonoid and anthocyanin biosynthetic enzymes and related transcription factors, genes sensitive to endogenous [sugars, abscisic acid (ABA)] and environmental (light) stimuli connected to drought stress, and genes developmentally regulated in ripening berries. Total anthocyanin content has increased at harvest in water-stressed (WS) fruits by 37-57% in two consecutive years. At least 84% of the total variation in anthocyanin content was explained by the linear relationship between the integral of mRNA accumulation of the specific anthocyanin biosynthetic gene UDP-glucose : flavonoid 3-O-glucosyltransferase (UFGT) and metabolite content during time series from véraison through ripening. Chalcone synthase (CHS2, CHS3) and flavanone 3-hydroxylase (F3H) genes of the flavonoid pathway showed high correlation as well. Genes coding for flavonoid 3',5'-hydroxylase (F3'5'H) and O-methyltransferase (OMT) were also up-regulated in berries from dehydrated plants in which anthocyanin composition enriched in more hydroxylated and more methoxylated derivatives such as malvidin and peonidin, the grape anthocyanins to which human gastric bilitranslocase displays the highest affinity. The induction in WS plants of structural and regulatory genes of the flavonoid pathway and of genes that trigger brassinosteroid hormonal onset of maturation suggested that the interrelationships between developmental and environmental signalling pathways were magnified by water deficit which actively promoted fruit maturation and, in this context, anthocyanin biosynthesis.
authors: Dipartimento di Scienze Agrarie e Ambientali, University of Udine, via delle Scienze 208, 33100 Udine, Italy.
authors: Simone D
authors: SD
authors: Castellarin
authors: Antonella
authors: A
authors: Pfeiffer
authors: Paolo
authors: P
authors: Sivilotti
authors: Mirko
authors: M
authors: Degan
authors: Enrico
authors: E
authors: Peterlunger
authors: Gabriele
authors: G
authors: DI Gaspero
mesh_terms: D000872:Anthocyanins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D005638:Fruit / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D015394:Molecular Structure; D012621:Seasons; D012987:Soil; D013997:Time Factors; D014158:Transcription, Genetic; D027843:Vitis / Q000235:genetics* / Q000502:physiology; D014867:Water / Q000378:metabolism*
chemical_list: D000872:Anthocyanins; D012987:Soil; D014867:Water