The Roles Of Scavenger Receptors In Endoparasitiod Wasp,Micropilits Mediator

Micropilits mediator,a kind of endoparasitiod wasp,is an enemy of a large number of agricultural pests,including Helicoverpa armigera,Pseudaletia separate,Mamestra brassicae and other lepidopteran insects.Scavenger receptors(SCRs)are a family of transmembrance glycoproteins that are involved in the recognition of variety of pathogens.Here,we identified and characterized thirteen SCR genes from the endoparasitoid wasp,Micropilits mediator and,investigated the function of MmSCRs in the development and immunity of the parasitoid wasp.We analyzed the evolutionary relationship of SCRs from other species,used quantitative Real-Time PCR(qRT-PCR)to analyze transcriptional levels of MmSCR genes in different developmental stages and in response to bacterial infections.To explore the functions of SCRs in the parasitoid wasp,we knock-downed MmSCRA-1 and MmCD36-1 gene expression using RNA interference.The results are as following:(1)Micropilits mediator scavenger receptors constitute a family of thirteen members,including three types: four type A members,eight type B members and one type C member.(2)The expressional level of MmSCRA-1 gene is higher compared to other MmSCR genes in different development stage.The expressional level of MmCD36-1 gene is higher post infection with Gram-positive bacteria Micrococcus luteus and Gram-negative bacteria Enterobacter colacae.(3)Eclosion rate of 3-day-old and 3.5-day-old pupa after MmSCRA-1 gene knockdown were significantly reduced.(4)After RNAi-based MmCD36-1 gene silencing,the survival of wasps has no obviously difference compared to control group.MmCD36-1 gene knockdown-wasps are more susceptible to E.colacae than M.luteus challenge.(5)Post infection with M.luteus or E.colacae,the bacterial loads were significantly higher in MmCD36-1 gene silenced wasps than the control group.Collectively,our data demonstrated that MmSCRA-1 might be involved in the development of M.mediator.MmCD36-1 is required for elimination of M.luteus and E.colacae efficiently to protect M.mediator from bacterial infection.