Functional Verification And Pathogeniaity Analysis Of Pathogenesis Related Gene Vdphb From Verticillium Wilt On Cotton

Verticillium Wilt is a worldwide pest of soil borne fungal vascular bundle,which will cause billions of dollars in economic loss in the worldwide every year.It is difficult to prevent and control of Verticillium wilt pathogen because of its strong survival ability,long survival time,wide host range and many ways of replanting.Cotton Verticillium wilt has become the main limiting factor of cotton production in China,so it is urgent to find a way to effectively control cotton Verticillium wilt.It is of great significance to study the pathogenesis of verticillium and to find out the methods to control the disease.In the previous study,our lab found a protein VdPHB which can interact with cotton resistance protein GbSBT1 by the pull-down method.To study the role of VdPHB gene in the pathogenic process of verticillium wilt and its related pathogenesis,we used agrobacterium mediated fungal transgenation to transfer the VdPHB gene knockout vector into the cells of verticillium wilt,the VdPHB gene was lost by gene homologous recombination principle.The physiological and biochemical phenotypes of the ΔVdphb mutants were analyzed to explore the function of the gene.The experimental results and main conclusions of this study are as follows: 64 transformants were obtained by agrobacterium mediated transformation of fungi.10 transformants were randomly selected,and 2 ΔVdphb mutants,which named ΔVdphb-14 and ΔVdphb-16,were obtained by PCR and qRT-PCR analysis.We analysised growth rate,extracellular enzyme activity and pathogenicity of wild type Vd991 and ΔVdphb mutants.The growth rate and extracellular enzyme activity analysis showed that there was no significant difference between ΔVdphb mutants and wild type Vd991.The pathogenicity analysis showed that the virulence of the ΔVdphb mutants were significantly lower than wild type Vd991.The vascular bundles in the cotton rods infected by the ΔVdphb mutants did not change to brown when observing the stem section of the susceptible plants.While vascular bundles in the cotton rods infected by Vd991 became brown.These results suggest that VdPHB gene is not involved in regulation of Verticillium dahliae growth and extracellular enzyme activity,and VdPHB gene may play a role on Cotton Verticillium dahliae infection in the colonization process.