The Key Laboratory of Oasis Eco-Agriculture, College of Agriculture, Shihezi University, Shihezi, Xinjiang, 832000, China.
State Key Laboratory of Plant Genomic, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
Environ Microbiol. 2018 Apr;20(4):1607-1621. doi: 10.1111/1462-2920.14101. Epub 2018 Apr 10.
The vascular wilt fungus Verticillium dahliae is one of the most destructive pathogens of cotton (Gossypium hirsutum) and many other economically important dicot plants. Fungal pathogens require Myosin-mediated actomyosin motility system for colonization of their host plants; however, the mechanisms underlying this process have not been fully characterized for V. dahliae. Here, in a knock-out experiment, we characterized the role of VdMyo5, a member of the Myosin V family, before and during infection of cotton and Arabidopsis thaliana. The VdMyo5 deletion mutant (ΔVdmyo5) fungi showed obvious defects in the development of conidia and the polarized elongation of vegetative hyphae, but no inhibition of host root penetration. Overall, the ΔVdmyo5 fungi exhibited dramatically reduced virulence in cotton and Arabidopsis, with almost no colonization in sections of host vascular tissue. We found labelled Myosin5-GFP to be specifically enriched at the hyphal tip, co-localized with FM4-64 labelled Spitzenkörper, which is the vesicle supply centre in filamentous fungi. Comparative secretome analysis revealed that proteins associated with cell wall modification and degradation of reactive oxygen species were significantly altered in mutant strains. Our results indicate that Myosin5 is required for vegetative growth and full virulence, possibly by regulating vesicle transport. The findings provide important insight into the cellular mechanisms of Verticillium pathogenesis.
萎蔫病菌是棉花（Gossypium hirsutum）和许多其他重要双子叶植物的最具破坏性的病原体之一。真菌病原体需要肌球蛋白介导的肌动球蛋白运动系统来定植其宿主植物；然而，对于 V. dahliae，这一过程的机制尚未完全阐明。在这里，在敲除实验中，我们在棉花和拟南芥感染前后，对肌球蛋白 V 家族的一员 VdMyo5 的作用进行了表征。VdMyo5 缺失突变体（ΔVdmyo5）真菌在分生孢子的发育和营养菌丝的极化伸长方面表现出明显的缺陷，但对宿主根穿透没有抑制作用。总的来说，ΔVdmyo5 真菌在棉花和拟南芥中的毒力显著降低，在宿主血管组织的切片中几乎没有定殖。我们发现标记的 Myosin5-GFP 特异性富集在菌丝顶端，与 FM4-64 标记的 Spitzenkörper 共定位，后者是丝状真菌中的囊泡供应中心。比较分泌组分析显示，与细胞壁修饰和活性氧降解相关的蛋白质在突变株中明显改变。我们的结果表明肌球蛋白 5 对于营养生长和完全毒力是必需的，可能通过调节囊泡运输。这些发现为萎蔫病发病机制的细胞机制提供了重要的见解。
