Preliminary Study On The Fuction Of Four Polygalacturonase Genes In Valsa Mali

Valsa mali., the causal agent of Valsa canker of apple tree, has been a serious threat toapple production in whole China. Although the disease prevention and control oftechnologies have done a lot of research, there are no the essential strategies. Understandingpathogenicity-relate genes and then futher study of the pathogenic mechanisms of Valsa Mali..will provide better understanding of this fungus and effective prevention and control measuresIn this experiment, the four polygalacturonase genes Vmpgx-1, Vmpgx-2, Vmpgx-3andVmpgx-4in Valsa mali were knockout by molecular biology techniques. The results are asfollows:1、The knockout vectors were constructed though Double-joint PCR. Then, using thePEG-mediated transformation, the four genes Vmpgx-1, Vmpgx-2, Vmpgx-3and Vmpgx-4were respectively obtained mutants213,341,95,382by gene knockout.2、The gene deletion mutants were respectively2,2,1,1by PCR and Southern Blot.3、The gene deletion mutants were analysed through observation colony morphology,colony color, colony growth rate, the number of propagules and pathogenicity. Comparedwith the wild type03-8, the biological analysis of the gene deletion mutants were nosignificant difference. However, the pathogenicity of the gene deletion mutants weresignificantly decreased. Therefore, the four polygalacturonase genes were associated withpathogenicity of Valsa Mali.4、After verification of complement, pathogenicity of mutants were similar to wild-type03-8, further proofing the defects of pathogenicity of the deletion mutants caused by the geneknockout.In this experiment, the four genes were associated with pathogenicity of Valsa Mali byanalyzing the preliminary function of four polygalacturonase genes. This study will lay atheoretical foundation for analyzing pathogenetic mechanism of Valsa Mali.