Background

The sucrose non-fermenting 1-related kinases 2 (SnRK2s) play important roles in osmotic stress responses in A. thaliana and rice (Oryza sativa L.). Osmotic stress/ABA–activated protein kinase 2 (SAPK2) is a member of SnRK2s subclass II in rice, but its function in rice yield under drought stress is unclear.

Results

Compared with wild-type (Oryza.Sativa L.spp.japonica, WT) plants, the sapk2 rice mutant lines were shorter and produced fewer grains per panicle, smaller grains and lower grain yield under reproductive stage drought stress (RDS). Subsequent analysis suggested that SAPK2 considerably influences the nitrogen, phosphorus, and potassium contents of rice grains. The examination of rice seedling growth and development under nutrient-deprived conditions (−N, −K, and − P) proved that SAPK2 can significantly affect rice seedling growth and root development in hydroponic cultures lacking N and K. Moreover, the NO₃⁻ influx rate and nitrate concentration analysis indicated that SAPK2 promotes nitrate uptake and assimilation by regulating nitrate-related transporters.

Conclusion

These results suggest that SAPK2 could enhance grain production by regulating nitrogen utilization efficiency under RDS. Our work provided insights to breeding drought tolerant rice with high nutrient uptake.

中文翻译：

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SAPK2通过调节生育期干旱胁迫下的氮代谢过程来促进水稻产量。

背景

蔗糖非发酵型1相关激酶2（SnRK2s）在拟南芥和水稻（Oryza sativa L.）的渗透胁迫应答中起重要作用。渗透胁迫/ ABA激活蛋白激酶2（SAPK2）是水稻SnRK2s II类的成员，但在干旱胁迫下其在水稻产量中的作用尚不清楚。

结果

与野生型（Oryza.Sativa L.spp.japonica，WT）植物相比，在生育期干旱胁迫（RDS）下，sapk2水稻突变体株系较短，单穗粒数减少，籽粒更小，单产降低。随后的分析表明，SAPK2在很大程度上影响水稻籽粒的氮，磷和钾含量。证明，SAPK2可以显著影响水稻幼苗在缺乏N和K.另外，NO水耕培养物的生长和根发育- （P-N，-K，和）的水稻秧苗营养剥夺的条件下生长和发育的检查₃ ^-入渗速率和硝酸盐浓度分析表明，SAPK2通过调节硝酸盐相关转运蛋白来促进硝酸盐吸收和同化。

结论

这些结果表明，SAPK2可以通过调节RDS下的氮利用效率来提高谷物产量。我们的工作为选育具有高养分吸收能力的耐旱水稻提供了见识。