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First published online September 16, 2005; 10.1104/pp.105.064238 Plant Physiology 139:652-663 (2005) © 2005 American Society of Plant Biologists Proanthocyanidin Synthesis and Expression of Genes Encoding Leucoanthocyanidin Reductase and Anthocyanidin Reductase in Developing Grape Berries and Grapevine Leaves1,[w]Commonwealth Scientific and Industrial Research Organization, Plant Industry, Horticulture Unit, Glen Osmond, South Australia 5064, Australia (J.B., M.O.D., J.S.H., S.P.R.); Cooperative Research Centre for Viticulture, Glen Osmond, South Australia 5064, Australia (J.B., J.S.H., S.P.R.); and Commonwealth Scientific and Industrial Research Organization, Plant Industry, Canberra, Australian Capitol Territory 2601, Australia (A.R.A., G.J.T.)
Proanthocyanidins (PAs), also called condensed tannins, can protect plants against herbivores and are important quality components of many fruits. Two enzymes, leucoanthocyanidin reductase (LAR) and anthocyanidin reductase (ANR), can produce the flavan-3-ol monomers required for formation of PA polymers. We isolated and functionally characterized genes encoding both enzymes from grapevine (Vitis vinifera L. cv Shiraz). ANR was encoded by a single gene, but we found two highly related genes encoding LAR. We measured PA content and expression of genes encoding ANR, LAR, and leucoanthocyanidin dioxygenase in grape berries during development and in grapevine leaves, which accumulated PA throughout leaf expansion. Grape flowers had high levels of PA, and accumulation continued in skin and seeds from fruit set until the onset of ripening. VvANR was expressed throughout early flower and berry development, with expression increasing after fertilization. It was expressed in berry skin and seeds until the onset of ripening, and in expanding leaves. The genes encoding LAR were expressed in developing fruit, particularly in seeds, but had low expression in leaves. The two LAR genes had different patterns of expression in skin and seeds. During grape ripening, PA levels decreased in both skin and seeds, and expression of genes encoding ANR and LAR were no longer detected. The results indicate that PA accumulation occurs early in grape development and is completed when ripening starts. Both ANR and LAR contribute to PA synthesis in fruit, and the tissue and temporal-specific regulation of the genes encoding ANR and LAR determines PA accumulation and composition during grape berry development.
1 This research was supported by an Australian Postgraduate Award and by the Grape and Wine Research and Development Corporation. 2 Present address: Department of Primary Industries, P.O. Box 905, Mildura, Victoria 3502, Australia. 3 Present address: Grape and Wine Research and Development Corporation, P.O. Box 221, Goodwood, South Australia 5034, Australia. [w] The online version of this article contains Web-only data. Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.105.064238. * Corresponding author; e-mail simon.robinson{at}csiro.au; fax 61–8–8303–8601. Received April 13, 2005; returned for revision June 13, 2005; accepted June 15, 2005. This article has been cited by other articles:
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