Extracellular superoxide dismutase VdSOD5 is required for virulence in Verticillium dahliae  

作　　者：TIAN Li HUANG Cai-min ZHANG Dan-dan LI Ran CHEN Jie-yin SUN Wei-xia QIU Nian-wei DAI Xiao-feng 

机构地区：[1]College of Life Science,Qufu Normal University,Qufu 273165,P.R.China [2]State Key Laboratory for Biology of Plant Diseases and Insect Pests/lnstitute of Plant Protection,Chinese Academy of Agricultural Sciences,Beijing 100193,P.R.China

出　　处：《Journal of Integrative Agriculture》2021年第7期1858-1870,共13页农业科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (31501588, 31972228, and 31970142)。

摘　　要：Plants produce reactive oxygen species(ROS) to defend pathogens. To counteract this attack, certain pathogens express superoxide dismutases(SODs) to scavenge host-derived ROS. However, the roles of SODs in Verticillium dahliae, an important vascular pathogen, are not clear. Our previous study has shown that a putative extracellular SOD(VdSOD5) of V. dahliae is significantly induced by culturing in cotton tissues, suggesting that VdSOD5 may play an important role in host–pathogen interactions and virulence. Here, we showed that VdSOD5 encoded a superoxide dismutase with a cofactor copper-binding site and a functional signal peptide that can conduct protein secretion in an invertase-mutated yeast strain. The mutations in VdSOD5(ΔVdSOD5) did not change the normal vegetative growth and conidial production but reduced the virulence of V. dahliae on susceptible host cotton. Further studies showed that the transcription of Vd SOD5 was significantly up-regulated during the early stage of infection, and the loss-of-function of VdSOD5 decreased culture filtrate and fungal tissue SOD activities of V. dahliae by 74 and 28%, respectively. Compared to the wild-type strain Vd991, the ΔVdSOD5 showed the same sensitivity to the intracellular ROS generator menadione. Furthermore, nitroblue tetrazolium(NBT) staining demonstrated that VdSOD5 functioned in the detoxification of superoxides generated by host roots during infection. These results suggest that VdSOD5 of V. dahliae is an important virulence factor, secreted out of cells to combat host-derived ROS.

关 键 词：Verticillium dahliae superoxide dismutase SECRETION VIRULENCE ROS detoxification 

分 类 号：S432.4[农业科学—植物病理学]