落叶型大丽轮枝菌脱落酸合成相关基因功能研究

为了探讨大丽轮枝菌中脱落酸（Absicisic acid，ABA）合成相关基因在致病过程中的功能，克隆大丽轮枝菌落叶型菌株XJ592的ABA合成相关基因Vdaba1、Vdaba2(1)、Vdaba2(2)和Vdaba4，采用同源重组的方法分别获得4个基因的敲除突变体菌株。生物学功能测定结果表明，Vdaba1主要参与促进大丽轮枝菌的产孢，Vdaba2(1)和Vdaba2(2)基因影响大丽轮枝菌的生长速率，Vdaba4基因参与调节大丽轮枝菌对氧化压力胁迫的响应。致病力测定结果表明，接种21 d时Vdaba1和Vdaba4基因突变体菌株的致病性显著低于野生型菌株XJ592，但在接种30 d时突变体与野生型XJ592接菌棉花植株的落叶率均为100%。

Functional Characterization of ABA Biosynthesis Genes in Defoliating Strain of Verticillium dahliae

Verticillium wilt caused by Verticillium dahliae is one of the most devastating diseases in cotton production. In order to explore the function of ABA biosynthesis genes during infection of V.dahliaeon cotton, the genes Vdaba1, Vdaba2(1), Vdaba2(2) and Vdaba4 were identified from wild type (WT) strain of XJ592, and the deletion strains of each gene were obtained by homologous recombination methods.Biological characters and pathogenicity of mutant strains were examined. The results showed thatVdaba1gene which contributed to conidial yield of V.dahliae.Vdaba2(1) and Vdaba2(2) showed obvious effect in the development of colony. But Vdaba4 gene significantly enhanced V.dahliae aggressiveness to oxidation stress.Pathogenicity assays indicated that virulence of Vdaba1 and Vdaba4 mutants significantly reduced compared with WT after inoculated cotton for 21 d. However, the rate of defoliated leaves of all mutants and WT were 100% at 30 days after inoculation.