College of Horticulture, China Agricultural University, Beijing, China.
Huasheng Seed Group Co. Ltd, Qingzhou, Shandong, 262500, China.
Plant Physiol Biochem. 2023 Sep;202:107928. doi: 10.1016/j.plaphy.2023.107928. Epub 2023 Aug 2.
CsCHYR1 (CHY ZINC-FINGER AND RING PROTEIN1) encodes a RING (Really Interesting New Gene) finger E3 ubiquitin ligase involved in ubiquitin-mediated protein degradation and plays an important role for cucumber to resist drought stress. Here, we obtain one of the candidate proteins CsCHYR1 that probably interacts with CsATAF1 by yeast-two hybrid screening. Subsequently, it is verified that CsCHYR1 interacts with CsATAF1 and has self-ubiquitination activity. When the cysteine residue at 180 in the RING domain of CsCHYR1 is replaced by serine or alanine, ubiquitin could not be transported from E2 to the substrate. CsCHYR1 ubiquitinates CsATAF1 and affects the stability of CsATAF1 when plants are subjected to drought stress. The expression level of CsCHYR1 is increased by 4-fold after ABA treatment at 9 h. The Atchyr1 mutants perform an ABA-hyposensitive phenotype and have a lower survival rate than Col-0 and CsCHYR1 Atchyr1 lines. In addition, CsCHYR1 interacts with CsSnRK2.6. Therefore, our study reveals a CsSnRK2.6-CsCHYR1-CsATAF1 complex to promote the drought stress response by decreasing CsATAF1 protein accumulation and inducing stomatal closure. Those findings provide new ideas for cucumber germplasm innovation from the perspective of biochemistry and molecular biology.
CsCHYR1（CHY 锌指和环蛋白 1）编码一个 RING（真正有趣的新基因）指 E3 泛素连接酶，参与泛素介导的蛋白质降解，在黄瓜抵抗干旱胁迫中起着重要作用。在这里，我们通过酵母双杂交筛选获得了一个候选蛋白 CsCHYR1，它可能与 CsATAF1 相互作用。随后，验证了 CsCHYR1 与 CsATAF1 相互作用，并具有自身泛素化活性。当 CsCHYR1 的 RING 结构域中的 180 位半胱氨酸残基被丝氨酸或丙氨酸取代时，泛素不能从 E2 转移到底物上。CsCHYR1 泛素化 CsATAF1，并影响 CsATAF1 在植物受到干旱胁迫时的稳定性。用 ABA 处理 9 h 后，CsCHYR1 的表达水平增加了 4 倍。Atchyr1 突变体表现出 ABA 低敏表型，其存活率低于 Col-0 和 CsCHYR1 Atchyr1 系。此外，CsCHYR1 与 CsSnRK2.6 相互作用。因此，我们的研究揭示了一个 CsSnRK2.6-CsCHYR1-CsATAF1 复合物，通过减少 CsATAF1 蛋白积累和诱导气孔关闭来促进干旱胁迫反应。这些发现为从生物化学和分子生物学的角度创新黄瓜种质资源提供了新的思路。
