Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences; Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization (MOA); Guangdong Province Key Laboratory of Tropical and Subtropical Fruit Tree Research, Guangzhou, 510640, China; Key Laboratory of Saline-Alkali Vegetation Ecology Restoration (SAVER), Ministry of Education; Alkali Soil Natural Environmental Science Center (ASNESC), Northeast Forestry University, Harbin 150040, China.
Key Laboratory of Saline-Alkali Vegetation Ecology Restoration (SAVER), Ministry of Education; Alkali Soil Natural Environmental Science Center (ASNESC), Northeast Forestry University, Harbin 150040, China.
Plant Sci. 2021 Feb;303:110685. doi: 10.1016/j.plantsci.2020.110685. Epub 2020 Sep 19.
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.
蔗糖非发酵-1 相关蛋白激酶 2（SnRK2）是植物中重要的与应激相关的植物蛋白激酶。拟南芥中已鉴定出 II 组和 III 组 SnRK2 的相互作用伙伴和磷酸化底物，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）筛选来寻找与拟南芥 AtSnRK2.4 相互作用的蛋白。AtSnRK2.4 是一种 I 组 SnRK2。转录因子 AtMYB21 被鉴定为 AtSnRK2.4 的相互作用伙伴，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。亚细胞定位测定表明，AtSnRK2.4 和 AtMYB21 位于洋葱表皮细胞的细胞质和细胞核中。AtSnRK2.4 和 AtMYB21 在许多组织中表达，并在 NaCl 胁迫下上调表达。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表现出增强的耐受性。此外，盐胁迫下 AtSnRK2.4 和 AtMYB21 转基因拟南芥中下游应激响应基因的表达上调。这些结果表明，AtSnRK2.4 可能与 AtMYB21 协同作用，通过上调下游应激响应基因来介导对盐胁迫的反应。
