Leucine-rich repeat receptor-like kinases (LRR-RLKs) have been widely associated with plant abiotic stress responses. However, the functions of the majority of LRR-RLKs has not been well defined. Here, we identified a novel rice LRR-RLK member involved in salt tolerance and designated as OsSTLK (Oryza sativa L. Salt-Tolerance LRR-RLK). Transcript analysis showed that OsSTLK was significantly induced in response to salt stress in rice shoot and root in a time and dosage-dependent fashion. Phenotypic observations indicated that OsSTLK overexpression exhibited reduced salt sensitivity, and improved salt stress tolerance. Further physiological analysis showed that OsSTLK overexpression remarkably reduced electrolyte leakage, malondialdehyde (MDA) content, reactive oxygen species (ROS) accumulation under salt stress conditions by up-regulating ROS-scavenging activities and modifying stomatal patterning. Moreover, Na+/K+ ratio and MAPK phosphorylation level were also reduced in OsSTLK-overexpression transgenic rice plants compared with WT control. Taken together, our findings suggested that OsSTLK as an important positive regulator of salt stress tolerance perhaps through regulating ROS scavenging system, Na+/K+ ratio and MAPK signal pathway.

中文翻译：

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富含亮氨酸的重复受体样激酶 OsSTLK 调节水稻的耐盐性

富含亮氨酸的重复受体样激酶 (LRR-RLKs) 与植物非生物胁迫反应广泛相关。然而，大多数 LRR-RLK 的功能还没有得到很好的定义。在这里，我们确定了一个涉及耐盐性的新型水稻 LRR-RLK 成员，并命名为 OsSTLK（Oryza sativa L. Salt-Tolerance LRR-RLK）。转录分析表明，OsSTLK 以时间和剂量依赖性方式显着诱导水稻芽和根响应盐胁迫。表型观察表明 OsSTLK 过表达表现出降低的盐敏感性和提高的盐胁迫耐受性。进一步的生理分析表明，OsSTLK 过表达显着降低了电解质泄漏、丙二醛 (MDA) 含量、通过上调 ROS 清除活性和改变气孔模式来减少盐胁迫条件下活性氧 (ROS) 的积累。此外，与 WT 对照相比，OsSTLK 过表达转基因水稻植株的 Na+/K+ 比和 MAPK 磷酸化水平也降低。综上所述，我们的研究结果表明 OsSTLK 作为盐胁迫耐受性的重要正调节剂可能通过调节 ROS 清除系统、Na+/K+ 比和 MAPK 信号通路。