Characterization of the ABA Receptor VlPYL1 That Regulates Anthocyanin Accumulation in Grape Berry Skin.

ABA plays a crucial role in controlling several ripening-associated processes in grape berries. The soluble proteins named as PYR (pyrabactin resistant)/PYL (PYR-like)/RCAR (regulatory component of ABA receptor) family have been characterized as ABA receptors. Here, the function of a grape PYL1 encoding gene involved in the response to ABA was verified through heterologous expression. The expression level of was highest in grape leaf and fruit tissues of the cultivar Kyoho, and the expression of was increased during fruit development and showed a reduction in ripe berries. Over-expression of enhances ABA sensitivity in Arabidopsis. Using the transient overexpression technique, the gene was over-expressed in grape berries. Up-regulation of the gene not only promoted anthocyanin accumulation but also induced a set of ABA-responsive gene transcripts, including and . Although tobacco rattle virus (TRV)-induced gene silencing (VIGS) was not successfully applied in the "Kyoho" grape, the application of the transient overexpression technique in grape fruit could be used as a novel tool for studying grape fruit development.