Sucrose non-fermenting-1-related protein kinase 2 s (SnRK2 s) are important stress-related plant protein kinases in plants. The interaction partners and phosphorylation substrates of group II and III SnRK2 s in Arabidopsis thaliana have been identified, but similar data for group I SnRK2 s are very limited. Here, we used a yeast two-hybrid (Y2H) screen to find proteins that interact with Arabidopsis AtSnRK2.4, a group I SnRK2. The transcription factor AtMYB21 was identified as an AtSnRK2.4 interaction partner, and its interaction with AtSnRK2.4 was confirmed by an in vitro pull-down assay and a bimolecular fluorescence complementation (BiFC) assay. A subcellular localization assay demonstrated that AtSnRK2.4 and AtMYB21 were located in the cytoplasm and nucleus of onion epidermal cells. AtSnRK2.4 and AtMYB21 were expressed in many tissues and upregulated in response to NaCl stress. Transgenic plants that overexpressed AtSnRK2.4 or AtMYB21 gene exhibited enhanced tolerance to salt stress at germination and post-germination stages. Moreover, the expression of downstream stress-responsive genes was upregulated in salt-stressed AtSnRK2.4 and AtMYB21 transgenic Arabidopsis. These results suggest that AtSnRK2.4 may act synergistically with AtMYB21 to mediate the response to salt stress through the upregulation of downstream stress-responsive genes.

中文翻译：

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拟南芥蔗糖非发酵 1 相关蛋白激酶 AtSnRK2.4 与参与耐盐性的转录因子 AtMYB21 相互作用

蔗糖非发酵 1 相关蛋白激酶 2 (SnRK2 s) 是植物中重要的胁迫​​相关植物蛋白激酶。拟南芥中 II 和 III 组 SnRK2 的相互作用伙伴和磷酸化底物已被鉴定，但 I 组 SnRK2 的类似数据非常有限。在这里，我们使用酵母双杂交 (Y2H) 筛选来查找与拟南芥 AtSnRK2.4（一组 I SnRK2）相互作用的蛋白质。转录因子 AtMYB21 被鉴定为 AtSnRK2.4 相互作用伙伴，其与 AtSnRK2.4 的相互作用通过体外下拉测定和双分子荧光互补 (BiFC) 测定得到证实。亚细胞定位分析表明 AtSnRK2.4 和 AtMYB21 位于洋葱表皮细胞的细胞质和细胞核中。在SnRK2。4 和 AtMYB21 在许多组织中表达，并响应 NaCl 胁迫而上调。过表达 AtSnRK2.4 或 AtMYB21 基因的转基因植物在萌发和萌发后阶段对盐胁迫的耐受性增强。此外，在盐胁迫的 AtSnRK2.4 和 AtMYB21 转基因拟南芥中，下游应激反应基因的表达上调。这些结果表明 AtSnRK2.4 可能与 AtMYB21 协同作用，通过上调下游应激反应基因来介导对盐胁迫的反应。4 和 AtMYB21 转基因拟南芥。这些结果表明 AtSnRK2.4 可能与 AtMYB21 协同作用，通过上调下游应激反应基因来介导对盐胁迫的反应。4 和 AtMYB21 转基因拟南芥。这些结果表明 AtSnRK2.4 可能与 AtMYB21 协同作用，通过上调下游应激反应基因来介导对盐胁迫的反应。