Apprehending siRNA Machinery and Gene Silencing in Brinjal Shoot and Fruit Borer, Leucinodes orbonalis.

Abstract

RNA interference (RNAi) technology is widely used in gene functional studies and has been shown to be a promising next generation alternative for insect pest management. To understand the efficiency of RNAi machinery in Leucinodes orbonalis (L. orbonalis) Guenee, a destructive pest of eggplant, core RNAi pathway genes Argonaute-2, Dicer-2, Loquacious, and Sid-1 were mined from the transcriptome and characterized. The transcript abundance of these genes was studied after exposure to exogenous double-stranded RNA (dsRNA). Domain structure analysis revealed that these genes have conserved domains required for the definite protein function in the siRNA pathway. The protein sequences when subjected to phylogenetic analysis showed a close relation with homologs obtained from Ostrinia sp. The insects fed with dsRNA designed for vacuolar sorting protein SNF7 gene showed significant downregulation at 48 h post treatment and about 79% larval mortality. The expression study of genes showed a significant spike in transcript abundance of Dicer-2, Argonatute-2, and downregulation of Loquacious at 24 and 48 h post dsRNA exposure. The results on siRNA machinery genes expression and target gene knockdown implies L. orbonalis has an ample response to exogenous dsRNA.