State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Int J Mol Sci. 2020 Aug 3;21(15):5565. doi: 10.3390/ijms21155565.
The mitogen-activated protein kinase (MAPK) LjMPK6 is a phosphorylation target of SIP2, a MAPK kinase that interacts with SymRK (symbiosis receptor-like kinase) for regulation of legume-rhizobia symbiosis. Both LjMPK6 and SIP2 are required for nodulation in . However, the dephosphorylation of LjMPK6 and its regulatory components in nodule development remains unexplored. By yeast two-hybrid screening, we identified a type 2C protein phosphatase, LjPP2C, that specifically interacts with and dephosphorylates LjMPK6 in vitro. Physiological and biochemical assays further suggested that LjPP2C phosphatase is required for dephosphorylation of LjMPK6 in vivo and for fine-tuning nodule development after rhizobial inoculation. A non-phosphorylatable mutant variant LjMPK6 (T224A Y226F) could mimic LjPP2C functioning in MAPK dephosphorylation required for nodule development in hairy root transformed plants. Collectively, our study demonstrates that interaction with LjPP2C phosphatase is required for dephosphorylation of LjMPK6 to fine tune nodule development in .
丝裂原活化蛋白激酶（MAPK）LjMPK6 是 SIP2 的磷酸化靶标，SIP2 是一种 MAPK 激酶，与 SymRK（共生受体样激酶）相互作用，调节豆科植物-根瘤菌共生。LjMPK6 和 SIP2 都需要在 中进行结瘤。然而，在结瘤发育过程中 LjMPK6 和其调节成分的去磷酸化仍然未知。通过酵母双杂交筛选，我们鉴定了一种 2C 型蛋白磷酸酶 LjPP2C，它可以特异性地与 LjMPK6 相互作用并在体外使其去磷酸化。生理和生化分析进一步表明，LjPP2C 磷酸酶在体内 LjMPK6 的去磷酸化以及根瘤菌接种后精细调节结瘤发育是必需的。一种不可磷酸化的突变变体 LjMPK6（T224A Y226F）可以模拟 LjPP2C 在 hairy root 转化植物中结瘤发育所必需的 MAPK 去磷酸化中的功能。总之，我们的研究表明，与 LjPP2C 磷酸酶的相互作用是 LjMPK6 去磷酸化以精细调节 中结瘤发育所必需的。
