Silencing of apolipophorin-III causes abnormal adult morphological phenotype and susceptibility to Listeria monocytogenes infection in Tenebrio molitor

Abstract

Insect apolipophorin-III is an exchangeable protein that is abundantly found in the hemolymph, and serves an important role in lipid transport, development, and innate immunity. In this study, we examined the role of apolipophorin-III (TmapoLp-III) during the adult eclosion stages of Tenebrio molitor by RNA interference (RNAi) analysis. After silencing of the mRNA transcripts at both larval and pupal stages, adult phenotypic defects were noticed. Defects included the incomplete shedding of pupal skin, shorter extension of the elytra, and improper folding of the hind wings. Most of the adults were malformed and died possibly due to dehydration. We also showed the involvement of TmapoLp-III in conferring resistance to T.molitor larvae against Listeria monocytogenes infection. Mortality was found to be lower in non-silenced intoxicated larvae while the TmapoLp-III silenced larvae showed a significant susceptibility after 7 days post-injection with a dose of 10(6)cfu/larvae.