Downy mildew is one of the most serious diseases threatening grapevine cultivation. The PYR/PYL/RCAR proteins, which act as abscisic acid (ABA) receptors, are multifunctional, highly conserved, and reportedly play a crucial role in plant stress resistance in the ABA signaling pathway. In this study, we cloned a putative abscisic acid receptor gene, VvPYL4, from the ‘Beta’ grapevine cultivar. An analysis of the subcellular localization demonstrated that overexpressed VvPYL4 was localized in both the cytoplasm and the nucleus. The resistance of grapevine cultivars to downy mildew increased after the application of the exogenous hormones MeJA and ABA. The expression of VvPYL4 was significantly induced when exposed to Plasmopara viticola, MeJA, and ABA. The transcript of the VvPYL4 gene in ‘Beta’ grapevine leaves treated with tobacco rattle virus-induced gene silencing (VIGS) was significantly down-regulated. Silencing VvPYL4 had a slight effect on P. viticola resistance. Furthermore, silencing VvPYL4 significantly altered the transcripts of ABA and JA responsive genes, including the ABA signaling pathway-related genes ABF1, SnRK2.2, and PP2C2, as well as the genes related to the JA signaling pathway, MYC2, JAR1, and JAZ. Altogether, the data provide new evidence that VvPYL4 positively regulates grapevine response to downy mildew. This study also discusses the regulation mechanism of VvPYL4 on ABA and JA signaling transduction. Finally, these results provide a basis for additional research on the mechanisms behind grapevine resistance to downy mildew.

霜霉病是威胁葡萄种植的最严重疾病之一。PYR / PYL / RCAR蛋白是脱落酸（ABA）受体，具有多功能，高度保守性，据报道在ABA信号传导途径中对植物抗逆性起着至关重要的作用。在这项研究中，我们从“ Beta”葡萄品种中克隆了一个假定的脱落酸受体基因VvPYL4。对亚细胞定位的分析表明，过表达的VvPYL4位于细胞质和细胞核中。施用外源激素MeJA和ABA后，葡萄品种对霜霉病的抗性增强。VvPYL4的表达被暴露于葡萄绒单胞菌，MeJA和ABA。用烟草摇铃病毒诱导的基因沉默（VIGS）处理的“贝塔”葡萄叶片中VvPYL4基因的转录明显下调。沉默VvPYL4对轻微影响P.霜霉病抗性。此外，沉默VvPYL4会显着改变ABA和JA响应基因的转录本，包括ABA信号通路相关基因ABF1，SnRK2.2和PP2C2，以及与JA信号通路相关的基因MYC2，JAR1和JAZ。。总而言之，这些数据提供了新的证据证明VvPYL4积极调节葡萄对霜霉病的反应。本研究还探讨了VvPYL4对ABA和JA信号转导的调控机制。最后，这些结果为进一步研究葡萄对霜霉病的抗性机理提供了基础。