The Mechanism Of Myzus Persicae Transmitting Cucumber Mosaic Virus

Myzus persicae(Sulzer)(Homoptera:Aphididae),is one of the most important agricultural pests worldwide.In addition to sucking phloem sap,M.persicae also transmits plant viruses as a vector.This could lead to a big loss in crop yield.Aphids transmit cucumber mostaic virus(CMV)in a non-persistent manner.The time of aphids acquiring and inoculating virus is extremely rapid(seconds to minutes)and the ability to transmit virus is also short-lived(minutes to hours).However,little is known about the transmission mechanism of CMV.On one hand,the roles of M.persicae cuticle proteins in the transmission mechanism were studied with qPCR,Y2H and RNAi.On the other hand,potential receptors were found between RNA-seq and iTRAQ database.These results lay a theoretical foundation for the transmission mechanism of CMV.Moreover,they can offer the important reference for M.persicae and CMVcontrolled in agricultural industry.In this study,primers and conditions were firstly optimized for MPCP1,MPCP2,MPCP4,and MPCP5.The body and stylet templates were used to amplify MpCuPs and the gene sequences are consistent,so the body can be used as follow-up studies.Then we measured the relative amount of the gene encoding Cucumber mosaic virus capsid protein(CMV CP)and the transcript levels of four cuticle protein genes.The results show that the expression patterns of the four cuticle protein genes were almost identical,but the relative expression of MPCP1,MPCP2 and MPCP4 were higher than MPCP5.Yeast two-hybrid assays demonstrated that the protein encoded by MPCP4 gene was closely associated with the CMV CP through the direct interaction.Moreover,the ability of M.persicae to acquire CMV was suppressed by RNA interference of MPCP4.All these lines of evidence indicate that MPCP4,as a viral putative receptor in the stylet of aphid,plays an important role in aphid acquisition of CMV.In this study,an integrative analysis of the transcriptome and proteome was performed to identify important receptors involved in CMV transmission.At the transcript level,a total of 20550 genes were identified as differentially expressed genes(DEGs)at 24 h after transferred to infected tobacco plants using RNA-seq approach.Of these,9732 were up-regulated and 10,818 were down-regulated.In the KEGG database,the DEGs were mapped to 501 pathways.Among these,32 pathways were substantially enriched(p-value<0.05)between the up-regulated and the down-regulated DEGs.Examples of enriched pathways include cAMP signaling pathway and drug metabolism.At the protein level,a total of 744 proteins were classified as being differentially expressed between viral and nonviral M.persicae using iTRAQ(isobaric tags for relative and absolute quantitation)analysis.Of these,437 were up-regulated and 307 were down-regulated.In this KEGG database,differentially expressed proteins(DEPs)were substantially enriched to 14 pathways(p-value<0.05),including fatty acid metabolism,carbon metabolism,and amino acid metabolism.The combined transcriptome and proteome analysis was shown some relevance.Specifically,it revealed 282 proteins had corresponding transcripts in the RNA-seq data.Of these,207 had the same direction of change(up-or down-regulation)in the two omics data sets,including cuticular proteins,ribosomal proteins and Cytochrome P450s.