Distribution And Genetic Diversity Of Mycovirus BbCV2 In Beauveria Bassiana In Jilin Province

Asian corn borer(Ostrinia furnacalis)is one of the important pests that reduce maize production.In order to reduce the chemical resistance of pests and improve food safety,biological control became more and more important.Beauveria bassiana is a common insect pathogenic fungus,it has the characteristics of high safety,wide host range,no resistance,and easy cultivation.It makes an important contribution to the protection of agricultural resources in China,especially in Jilin province.Mycoviruses are widely distributed in nature,and it has been found that B.bassiana was rich in virus resources.In previous research,a new virus has been identified in our laboratory from B.bassiana,and named Beauveria bassiana chrysovirus 2(Bb CV2),which was a member of family Chrysoviridae.It can reduce the virulence of host fungi B.bassiana,while increase its growth rate.The purpose of this study is to explore the distribution,genetic diversity and phylogenetic relationship of the Bb CV2 virus in B.bassiana collected from Asian corn borer in Jilin Province,understand the evolutionary origin of the virus and its epidemiology,to provide new idea for high virulence strains screening of B.bassiana.This study mainly includes three aspects: 1.Collect and identify the B.bassiana strains from the overwintering larvae of Asian corn borer in different collection sites in Jilin Province;2.Ds RNA was extracted from B.bassiana strains for viruses containing identification,and RT-PCR was used to verify whether it contained Bb CV2 virus;3.The sequences of RNA dependent RNA polymerase(Rd Rp)gene encoding virus replicase protein of Bb CV2 virus from different tested strains were amplified,to analyze the genetic diversity of the virus.The main results are as follows: 1.B.bassiana strains are common in Jilin Province.B.bassiana could be isolated by diapause / de-diapause treatment from overwintering larvae of Asian corn borer in Jilin Province;2.Ds RNA fungal virus was found in all collected B.bassiana strains randomly selected,and the virus was detected in all collected sites,which was accounted for 82.5% of the tested strains;3.Mega11 and Danstart were used to analyze the geneti..0c diversity of Rd Rp sequence of Bb CV2 virus.It was found that the genetic diversity of the virus was relatively stable.In conclusion,ds RNA virus was widely found in B.bassiana strains infected asian corn borer from different collection sites in Jilin Province,and Bb CV2 virus was detected in every collection site,the virus is widespread and may be an important factor leading to the reduction of pathogenicity of B.bassiana in the field;Genetic diversity analysis showed that the virus was relatively stable,indicating that the host B.bassiana had little effect on its epidemic in the population,and the interaction between the two needs to be further explored.