Diversity Of Mycoviruses From Wheat Sharp Eyespot Pathogen Rhizoctonia Cerealis And Their Effect On Host Growth Characteristics

Rhizoctonia has a wide range of hosts in the world and is the pathogen of many crop diseases,causing great economic losses.The sharp eyespot of wheat,which causd by Rhizoctonia cerealis Vander Hoeven,have become one of the most serious diseases during the production process of wheat all over the word,recent years.At present,the prevention and control of sharp eyespot of wheat mainly depends on chemical fungicides,but environmental pollution and drug resistance caused by chemical control have become increasingly serious,so it is necessary to find a new control method.Mycoviruses are widely distributed in all important groups of fungi,some of them may affect the virulence of their hosts,resulting in weak virulence,so that they can be used as a potential biological control resource for fungal diseases.It is necessary to study the mycovirus in R.cerealis and the effect that they may cause on their host,so that we can find out the mycovirus with biological control potential.In this study,50 strains of R.cerealis collected from several provinces of China were sequenced and analyzed by high-throughput sequencing for potential mycovirus in them.The types of ds RNA bands were correlated with colony morphology,growth rate and pathogenicity by extraction,purification and electrophoresis.The results showed that the mycovirus were widely distributed in R.cerealis,and there was the phenomenon of compound infection.Some of these viruses were found for the first time in R.cerealis and have great research value.The genomes of 21 new endornavirus were obtained from 5 strains of R.cerealis.According to phylogenetic analysis,18 of them were identified as Alphaendornavirus and 3 were identified as members of a novel species of Betaendornavirus.Some of these sequences have important characteristics different from those previously reported for endornavirus.In this study,we proved the widespread and diversity of endornavirus in R.cerealis and proposed to classify three Betaendornavirus as a novel species.This study deepens our understanding of the family of Endornaviridae,and is of great significance to supplement and understand the members of this family.This study also explored the method of virus-free against R.cerealis,and analyzed the difference of biological characteristics between the virus-free strains and their progenies.In addition to the final success of strains in the parts of ds RNA and observed the related virus-free strains compared with parents can produce some more obvious changes,to explore the host,relationship between viral ds RNA in R.cerealis and factors associated with virulence recession laid a solid technical foundation,in order to further study the phenomenon of weak virulence fungi,viruses and the host relationship provides a new train of thought.