The Preliminary Study On Function Of Pectate Lyase Genes In Valsa Mali

During the past20years, the apple industry has achieved rapid development in ourcountry, China now has become the world’s largest apple producers and consumers.With therapid development of apple industry, apple valsa canker has spread at a sharpen speed inevery apple planting area of China, especially in the northern of China.Traditional methods,such as physical control, chemical control and breeding methods, demonstrated helplessly toapple valsa canker.And for now, high resistent materials are also deficient and the occurrenceand development rule of apple valsa canker and the pathogenetic mechanism of Valsa mali isstill very indistinct to us, caused inefficient, blind and passive disease control work, and alsocaused serious yield and economic loss.Therefore, study can not be restricted only on theinvestigating of disease cycle, screening of medicine and breeding of resistant cultivar, butalso searching the key pathogenetic gene of Valsa mali.To reveal the molecular pathogenicmechanism of Valsa mali as early as possible and provide theoretical basis and methods fordisease prevention and control, by the system of PEG-mediated transformation which hasbeen set up by my lab and gene knockout technology, this experiment obtained one pectatelyase gene deletion mutant ΔVmpl-1-4of Valsa mali.And we systematically analyze thephenotypes and pathogenicity of ΔVmpl-1-4,found the preliminary function of the pectatelyase gene Vmpl-1of Valsa mali，what’s more, we have also proved that Vmpl-1played a roleabout the pathogenicity of Valsa mali.The results are as follows:1.According to the knowledge of bioinformatics, we got3pectate lyase genesVmpl-1,Vmpl-2,Vmpl-3from the genome of Valsa mali. Design primers to amplify up anddown streams of the target gene and HPH sequence as marker gene which is used to screenmutants.3pectate lyase genes knock out vectors are constructed by double-joint PCR andhomologous recombination.PCR detection shows that3pectate lyase genes knock out vectorsall have been constructed successfully.2.By the system of PEG-mediated transformation which has been set up by my lab, wegot mutants of3pectate lyase genes successfully.Finally,1mutant ΔVmpl-1-4was selectedout by PCR identification and southern blotting verification. 3.We have also made a detailed statistics and analysis on the pathogenicity of theknock-out mutant ΔVmpl-1-4strain and wild-type strain03-8by inoculating detached Fujiapple tree leaves and branches. The results showed that: ΔVmpl-1-4showed significantlyincreased on pathogenicity compared with wild-type strain03-8.