Proanthocyanidin Synthesis and Expression of Genes Encoding Leucoanthocyanidin Reductase and Anthocyanidin Reductase in Developing Grape Berries and Grapevine Leaves

Abstract

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.

Gene Expression and Metabolite Profiling of Developing Highbush Blueberry Fruit Indicates Transcriptional Regulation of Flavonoid Metabolism and Activation of Abscisic Acid Metabolism

“…The limitation of PA gene expression to young blueberry fruit is reminiscent of the pattern in grape, although in that system, VvANR and VvLAR gene expression is high in seeds and skin until just after ripening initiation (véraison; Bogs et al, 2005). Interestingly, in grape seeds, there is a dramatic spike in VvF3#H, VvDFR, and VvLAR2 expression at ripening initiation, while VvANR and VvANS are also expressed at high levels (Bogs et al, 2005.…”

“…Interestingly, in grape seeds, there is a dramatic spike in VvF3#H, VvDFR, and VvLAR2 expression at ripening initiation, while VvANR and VvANS are also expressed at high levels (Bogs et al, 2005. It has been suggested that this might correspond to a burst in flavan-3-ol monomer synthesis in seeds (Downey et al, 2003;Bogs et al, 2007).…”

Identification of Genes with Potential Roles in Apple Fruit Development and Biochemistry through Large-Scale Statistical Analysis of Expressed Sequence Tags

“…Anthocyanidin is produced from leucoanthocyanidin by LDOX and is also a precursor of anthocyanin and its derivatives. In grape (Vitis vinifera), tissue and temporalspecific regulation of ANR and LAR genes strongly influences PA accumulation and composition during berry development (Bogs et al, 2005). The ANR cluster MD013330 was strongly represented in GoldRush but absent in Royal Gala in libraries derived from young fruit tissues.…”

Vascular Function in Grape Berries across Development and Its Relevance to Apparent Hydraulic Isolation

“…Thermal cycling conditions were 95°C for 10 min followed by 40 cycles of 95°C for 30 s, 56°C for 30 s, and 60°C for 60 s. Both cDNA dilutions were run in duplicate. Gene transcripts were normalized to VvUbiquitin1 (TC32075; The Institute for Genomic Research database) by comparing the cycle threshold of the target gene with that of VvUbiquitin1 (Bogs et al, 2005). Gene expression was expressed as mean and SE calculated over all biological replicates.…”