大丽轮枝菌VdSCH9基因的功能研究

大丽轮枝菌是一种土传性植物病原真菌,可侵染多种植物并引发黄萎病。目前,人们关于大丽轮枝菌的侵染和致病机制的了解还很不深入。本文通过敲除大丽轮枝菌编码丝氨酸/苏氨酸的蛋白激酶基因VdSCH9,阐明了其在大丽轮枝菌生长发育及致病过程中的作用。SCH9基因在酵母中的表达与cAMP-PKA途径和TOR信号通路相关,对酵母的生长、压力响应和寿命等有重要作用。大丽轮枝菌VdSCH9敲除突变体的生长速率显著下降,菌落边缘菌丝更为稀疏,菌丝分枝减少,对棉花植株为害的平均病情指数为56.6,显著低于野生型和互补突变体的平均病情指数90.5和82.8,对茄子植株为害的平均病情指数为65.9,也显著低于野生型和互补突变体的平均病情指数91.1和89.8。另外,敲除突变体对于高渗透压、氧化还原压力、细胞膜和细胞壁完整性等压力条件的敏感性增强。因此,VdSCH9对于大丽轮枝菌的生长、压力响应及致病力均有重要作用。

Functional analysis of gene VdSCH9 in Verticillium dahliae

Verticillium dahliae is a soil-borne pathogenic fungus that causes Verticillum wilt with a broad range of host plants. At present the molecular infection mechanisms of the pathogen are poorly understood. The authors explored the function of gene VdSCH9 encoding serine/threonine protein kinase in colony growth and pathogenicity by knocking out VdSCH9 in the fungus. The gene SCH9 is found to be involved in the cAMP-PKA and TOR pathway in the yeast. It also plays an important role in colony growth, stress response and longevity of yeast. The ΔVdSCH9 mutant was significantly reduced in growth rate, and it was also defective in aerial hyphal growth and hyphal branching. The cotton pathogenicity assay shows that the disease index of ΔVdSCH9 mutant was 56.6, significantly lesser than that of wild type and complement mutant, being 90.5 and 82.8 respectively. The similar result was acquired for the VdSCH9-deleted mutant in pathogenicity index on eggplant plants, being 65.9 for ΔVdSCH9 strain, and 91.1 and 89.8 for wild type and complement mutants. The gene-deleted mutants were more sensitive under stresses of oxidation, hyperosmotion, and cell wall and membrane integrity. These results suggest that the gene VdSCH9 is evidently involved in colony growth, stress response and pathogenesis in V. dahliae.