Yan Jun, Wang Pengcheng, Wang Bangshing, Hsu Chuan-Chih, Tang Kai, Zhang Hairong, Hou Yueh-Ju, Zhao Yang, Wang Qiming, Zhao Chunzhao, Zhu Xiaohong, Tao W Andy, Li Jianming, Zhu Jian-Kang
Shanghai Center for Plant Stress Biology, and Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China.
Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana, United States of America.
PLoS Genet. 2017 Apr 18;13(4):e1006753. doi: 10.1371/journal.pgen.1006753. eCollection 2017 Apr.
MicroRNAs (miRNAs) regulate gene expression and play critical roles in growth and development as well as stress responses in eukaryotes. miRNA biogenesis in plants requires a processing complex that consists of the core components DICER-LIKE 1 (DCL1), SERRATE (SE) and HYPONASTIC LEAVES (HYL1). Here we show that inactivation of functionally redundant members of the SnRK2 kinases, which are the core components of abscisic acid (ABA) and osmotic stress signaling pathways, leads to reduction in miRNA accumulation under stress conditions. Further analysis revealed that the steady state level of HYL1 protein in plants under osmotic stress is dependent on the SnRK2 kinases. Additionally, our results suggest that the SnRK2 kinases physically associate with the miRNA processing components SE and HYL1 and can phosphorylate these proteins in vitro. These findings reveal an important role for the SnRK2 kinases in the regulation of miRNA accumulation and establish a mechanism by which ABA and osmotic stress signaling is linked to miRNA biogenesis.
微小RNA（miRNA）调控基因表达，在真核生物的生长发育以及应激反应中发挥关键作用。植物中的miRNA生物合成需要一个由核心组分Dicer样蛋白1（DCL1）、锯齿状蛋白（SE）和下弯叶片蛋白（HYL1）组成的加工复合体。本文我们表明，脱落酸（ABA）和渗透胁迫信号通路的核心组分SnRK2激酶功能冗余成员的失活，会导致胁迫条件下miRNA积累量减少。进一步分析表明，渗透胁迫下植物中HYL1蛋白的稳态水平依赖于SnRK2激酶。此外，我们的结果表明，SnRK2激酶与miRNA加工组分SE和HYL1在物理上相互作用，并且能够在体外使这些蛋白磷酸化。这些发现揭示了SnRK2激酶在调控miRNA积累中的重要作用，并建立了一种将ABA和渗透胁迫信号与miRNA生物合成联系起来的机制。
