Silencing of JHEH and EcR genes of Plutella xylostella (Lepidoptera: Plutellidae) through double stranded RNA oral delivery

Abstract Plutella xylostella (L.), Diamondback moth (DBM), is a notorious pest disrupting cruciferous crops across the world. Overuse of chemically synthesized insecticides as well as application of bio-pesticide like Bacillus thuringiensis has gained progressive resistance against them, resulting in DBM management failures. To overcome this, a more potential, non-chemical and safe technology like Ribonucleic acid interference (RNAi) is to be implemented. RNAi, is a reverse genetic tool with high sequence specificity, elicited by double-stranded RNA (dsRNA) for silencing the target genes. The objective of this study was to silence two candidate genes from DBM viz., Juvenile Hormone Epoxide hydrolase (PxJHEH) and Ecdysteroid receptor (PxEcR) involved in regulating metamorphosis and molting respectively. In this regard, we have custom designed the dsRNAs (500 bp) by cloning and sequencing the candidate genes and delivered it orally (non-invasive mode). Further, we have assessed the extent of down regulation of target genes with five concentrations of dsRNA (1, 2, 5, 10 and 20 μg/μl) at four time points (24, 48, 72 and 96 h). The extent of gene silencing and mortality recorded for both genes were proportional to the dsRNA concentration. Our study projects that PxJHEH and PxEcR genes would be good target for dsRNA mediated gene silencing in management of insect pests such as DBM in near future.