The Regulation Analysis Of MicroRNA And MRNA Associated With Cydia Pomonella Granulovirus Infection And Host Resistance

Codling moth(Cydia pomonella L.,CM)is one of the most severe invasive insects in China and widely distributed quarantinable pests around the world,which could destroy the pome fruit production industry and make huge economic loss.Cydia pomonella granulovirus(CpGV)has been widely used in organic orchards as an effective and environmentally friendly biocontrol agent.However,the phenomenon of CM resistance against CpGV occurred constantly in orchards of different countries and regions,since the decrease of susceptibility in field population of CM was found in 2005.For the better understanding of the host insect-virus interaction and finding potential targets for the field effect recovery of CpGV virus products,we performed the small RNA library and transcriptome sequencing of resistant and susceptible CM strain larvae challenged with CpGV-M isolate,focusing on the high-level resistance of CM larvae against CpGV in the present study.The first microRNAs and transcripts datasets of CpGV-M isolate(virus)and different CM strains(host)were established and carefully analyzed for the identification of differentially expressed miRNAs and its target genes,which might play important roles in regulatory of granulovirus replication and infection process and host insect resistance emergence.In the oral infected larvae of susceptible strain(S),the virus started replicate at 48 hpi and significantly increased over time,while the replication was delayed in resistant strain(R).There was a general expression pattern of virus infection in different host strains,which related mRNAs and miRNAs mainly affected the virion replication and dissertation in host larvae.Based on the comparison of host miRNA and mRNA datasets between different samples,a total of 21 miRNAs and its 827 target genes,as well as 367 DEGs were identified as resistance related factors.Furthermore,a correspondence list of miRNA-mRNA regulation was obtained,including 11 pairs of positive regulation and 6 pairs of negative regulation,which mostly associated with insect immune system and defense reactions.This study provides a close look of granulovirus infection process in vivo and host-virus interactions,a fundamental and potential target for better understanding of host insect resistance to the virus and development of CM biocontrol strategies.