Feng Wanzhen, Wang Jiansheng, Liu Xinyu, Wu Haowen, Liu Muxing, Zhang Haifeng, Zheng Xiaobo, Wang Ping, Zhang Zhengguang
Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095, China.
The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, 210095, China.
Stress Biol. 2022 Sep 20;2(1):41. doi: 10.1007/s44154-022-00063-0.
The mitotic exit network (MEN) pathway is a vital kinase cascade regulating the timely and correct progress of cell division. In the rice blast fungus Magnaporthe oryzae, the MEN pathway, consisting of conserved protein kinases MoSep1 and MoMob1-MoDbf2, is important in the development and pathogenicity of the fungus. We found that deletion of MoSEP1 affects the phosphorylation of MoMob1, but not MoDbf2, in contrast to what was found in the buddy yeast Saccharomyces cerevisiae, and verified this finding by in vitro phosphorylation assay and mass spectrometry (MS) analysis. We also found that S43 residue is the critical phosphor-site of MoMob1 by MoSep1, and proved that MoSep1-dependent MoMob1 phosphorylation is essential for cell division during the development of M. oryzae. We further provided evidence demonstrating that MoSep1 phosphorylates MoMob1 to maintain the cell cycle during vegetative growth and infection. Taken together, our results revealed that the MEN pathway has both distinct and conservative functions in regulating the cell cycle during the development and pathogenesis of M. oryzae.
有丝分裂退出网络（MEN）途径是一种重要的激酶级联反应，可调节细胞分裂的及时和正确进程。在稻瘟病菌稻瘟菌中，由保守蛋白激酶MoSep1和MoMob1 - MoDbf2组成的MEN途径对该真菌的发育和致病性很重要。我们发现，与在芽殖酵母酿酒酵母中发现的情况相反，MoSEP1的缺失会影响MoMob1的磷酸化，但不影响MoDbf2的磷酸化，并通过体外磷酸化测定和质谱（MS）分析验证了这一发现。我们还发现S43残基是MoSep1对MoMob1进行磷酸化的关键位点，并证明MoSep1依赖性的MoMob1磷酸化对于稻瘟菌发育过程中的细胞分裂至关重要。我们进一步提供证据表明，MoSep1磷酸化MoMob1以在营养生长和感染期间维持细胞周期。综上所述，我们的结果表明，MEN途径在调节稻瘟菌发育和致病过程中的细胞周期方面具有独特和保守的功能。
