桃蚜表皮蛋白基因MpCPR1的分子特征与功能分析OA

[Aim]This study aims to clarify the molecular characteristics of cuticular protein gene in the green peach aphid,Myzus persicae,and to explore the effects of silencing this gene on the survival and ability to defend against entomopathogenic fungi of M.persicae.[Methods]The cDNA sequence of the cuticular protein gene was identified from the M.persicae transcriptome via homology-based search.The sequence features of this gene were analyzed using bioinformatic software.RT-qPCR was used to detect the expression levels of this gene in the 1 st-4th instar nymphs,wingless female adults and winged female adults,as well as in the 3rd instar nymphs of M.persicae at 12 and 24 h after treatment with 10 mg/mL 20-hydroxyecdysone(20E).Gene silencing was performed via feeding the 3rd instar nymphs of M.persicae with dsRNA followed by infection with Beauveria bassiana Bb325 and Lecanicillium psalliotae Y6,and the mortality rate of M.persicae and median lethal time(LT50)values of the two fungi against the 3rd instar nymphs of M.persicae were determined.[Results]A cuticular protein gene,designated as MpCPR1(GenBank accession number:PX121433),was obtained from M.persicae.MpCPR1 DNA consists of four exons and three introns,containing a 624 bp open reading frame that encodes a protein of 207 amino acid residues.MpCPR1 protein sequence includes a signal peptide,a chitin-binding domain,and the conserved Reber & Riddiford(R&R)consensus.MpCPR1 was expressed in M.persicae at all the tested developmental stages,with the highest expression level in winged adult females.At 24 h after treatment of the 3rd instar nymphs with 20E,the expression level of MpCPR1 significantly increased to 4.33-fold as high as that in the control group.At 12 h after RNAi of MpCPR1 in the 3rd instar nymphs of M.persicae,the expression level of MpCPR1 decreased significantly to 15.30％of that in the control group,indicating successful gene silencing.At 48,72,96 and 120 h after MpCPR1 silencing in the 3rd instar nymphs,the mortality rates of M.persicae were 18.89％,31.11％,35.56％and 37.78％,respectively,which were significantly higher than those in the control group.Silencing of MpCPR1 significantly increased the susceptibility of M.persicae to B.bassiana Bb325 and L.psalliotae Y6.At 48 h after B.bassiana Bb325 and L.psalliotae Y6 infection,the corrected mortality rates of M.persicae in the MpCPR 1-silenced group reached 54.90％and 62.79％,respectively,which were significantly higher than those in the control group.The LT50 values of B.bassiana Bb325 and L.psalliotae Y6 against the 3rd instar nymphs of M.persicae in the MpCPR1-silenced group were significantly shortened by 23.12 and 8.90 h,respectively,as compared with those in the control group.[Conclusion]MpCPR1 plays an important role in the survival and defense against pathogenic fungi in M.persicae,and can serve as a potential target for sustainable management of M.persicae.