SnRK2 (sucrose non-fermenting 1-related protein kinases 2) protein kinase family involves in several abiotic stress response in plants. Although the regulatory mechanism of SnRK2 have been well demonstrated in Arabidopsis thaliana, their functions in rice are still largely unknown. Here, we report a SnRK2 family gene, OsSAPK8, can be strongly induced by abiotic stresses, including low-temperature, drought and high salt stress. The ossapk8 mutants showed lower tolerance to low-temperature, high salinity and drought stresses at the vegetative stages. Moreover, the expressions of marker genes for those abiotic stresses, e.g. OsDREB1, OsDREB2, OsNCED and OsRAB21, were downregulated in the ossapk8 mutants. We further confirmed that the yield was reduced in ossapk8 mutant lines compared with the wild type. Our results provide evidence for OsSAPK8 acting as a positive regulator in cold, drought, and salt stress responses.

中文翻译：

---

水稻 SnRK 蛋白激酶 OsSAPK8 在非生物胁迫反应中起正调节作用

SnRK2（蔗糖非发酵 1 相关蛋白激酶 2）蛋白激酶家族参与植物中的几种非生物胁迫反应。尽管 SnRK2 的调控机制已在拟南芥中得到很好的证明，但它们在水稻中的功能仍然未知。在这里，我们报告了一个 SnRK2 家族基因 OsSAPK8，它可以被非生物胁迫强烈诱导，包括低温、干旱和高盐胁迫。ossapk8 突变体在营养阶段对低温、高盐度和干旱胁迫的耐受性较低。此外，这些非生物胁迫的标记基因的表达，例如 OsDREB1、OsDREB2、OsNCED 和 OsRAB21，在 ossapk8 突变体中被下调。我们进一步证实，与野生型相比，ossapk8 突变系的产量降低。