| Abstract Detail
Environmental Physiology Castellarin, S.D. [1], Gambetta, G.A. [2], Matthews, M.A. [3]. Applied water deficits accelerate ripening and induce changes in gene expression regulating flavonoid biosynthesis in grapevine. Irrigation is illegal in many wine growing regions throughout Europe in part due to the traditional view that water deficits promote winegrape quality. Experimentally, water deficits consistently promote one quality parameter, higher concentrations of anthocyanins in red winegrapes and their wines. However, controversy remains as to whether there is any direct effect on berry metabolism other than inhibition of growth. In the current study we examined the effect of early (ED) and late (LD) season water deficits, applied before or after the onset of ripening (véraison), on flavonoid biosynthesis in field grown Vitis vinifera 'Cabernet Sauvignon'. ED accelerated the ripening process. Accordingly, in ED berries anthocyanins and sugar accumulated more rapidly than in control berries. Both ED and LD increased anthocyanin accumulation throughout the whole course of berry maturation. Expression profiling revealed that the increased anthocyanin accumulation resulted from concordant increases in the expression of anthocyanin biosynthetic genes. Many of the genes controlling flux through the anthocyanin biosynthetic pathway were induced earlier in ED berries, including F3H, DFR, UFGT and GST. Increases in total anthocyanins result predominantly from an increase of 3’4’5’-hydroxylated forms through the differential regulation of F3’H and F3’5’H. Flavonols, and associated FLS1 expression, were higher in ED and LD treatments but without statistical differences. These results demonstrate that manipulation of abiotic stress, through applied water deficits, not only modulates compositional changes during berry ripening, but also the developmental timing of the ripening process itself. Log in to add this item to your schedule
1 - University of Udine, Italy I-33100, Dipartimento di Scienze Agrarie e Ambientali 2 - University of California, Davis, CA 95616, Department of Viticulture and Enology 3 - University of California at Davis, Department of Viticulture and Enology, 1 Shields Ave., Davis, CA, 95616, USA
Keywords: Water stress anthocyanin flavonol.
Presentation Type: Plant Biology Abstract Session: P Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton Date: Sunday, July 8th, 2007 Time: 8:00 AM Number: P01011 Abstract ID:328 |