Cold stress seriously affects the plant growth and development. The ubiquitination system plays an important role by degrading and modifying substrates at the protein level. In this study, the U-box type ubiquitin ligase VviPUB19 gene was induced by low temperature (4°C) in grapevine. In Arabidopsis thaliana, the pub19 mutant, a homologous mutation of VviPUB19, exhibited enhanced cold tolerance, and the resistance phenotype of the mutant could be attenuated by VviPUB19. VviPUB19 overexpressing grape lines exhibited lower cold tolerance. Furthermore, it was revealed that VviPUB19 interacted with the cold-related transcription factors VviICE1, 2 and 3 and VviCBF1 and 2, and was involved in the degradation of them. This is the first time that an E3 ligase (VviPUB19) that interacts with CBFs and affects its protein stability has been identified. It was also shown that VviICE1, 2 and 3 positively regulated VviPUB19 promoter activity. Therefore, our results suggest that VviPUB19 reduces grape cold tolerance via participating in the CBF-dependent pathway.

中文翻译：

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泛素连接酶 VviPUB19 通过影响 ICEs 和 CBF 的稳定性来负向调节葡萄的耐寒性


冷应激严重影响植物的生长发育。泛素化系统通过在蛋白质水平降解和修饰底物而发挥重要作用。本研究在葡萄藤中低温 （4°C） 诱导 U 盒型泛素连接酶 VviPUB19 基因。在拟南芥中，pub19 突变体（VviPUB19 的同源突变体）表现出增强的耐寒性，并且突变体的耐药表型可以被 VviPUB19 减弱。过表达 VviPUB19 的葡萄品系表现出较低的耐寒性。此外，发现 VviPUB19 与寒冷相关转录因子 VviICE1 、 2 和 3 以及 VviCBF1 和 2 相互作用，并参与它们的降解。这是首次发现与 CBF 相互作用并影响其蛋白质稳定性的 E3 连接酶 （VviPUB19）。研究还表明，VviICE1 、 2 和 3 正向调节 VviPUB19 启动子活性。因此，我们的结果表明 VviPUB19 通过参与 CBF 依赖性途径降低葡萄耐寒性。