RNA interference targeting cytochrome P450 cyp303a1 on the performance of Henosepilachna vigintioctopunctata

CYP303A1 is vital for metamorphosis in Locusta migratoria and Drosophila melanogaster. Here we uncovered that RNA interference (RNAi) against Hvcyp303a1 in the third instar larvae in a Coleopteran Henosepilachna vigintioctopunctata caused severe phenotypic defects. The Hvcyp303a1 RNAi larvae grew slowly, had thin head capsule and soft scoli, and ate less potato foliage. They arrested development at the fourth instar stage, gradually blackened and shrank, and eventually died. Knockdown of Hvcyp303a1 at the fourth-instar period led to similar defective phenotypes. Depletion of Hvcyp303a1 at the pupal period seriously impaired adult eclosion and resulted in misshapen adults. Comparison of transcriptomic data in Hvcyp303a1 RNAi to these in control larvae revealed that suppression of Hvcyp303a1 may disrupt biosynthesis of both 20E and JH, and metabolism of amino acids and sugars. Consistently, RNAi targeting Hvcyp303a1 repressed the expression of 4 Halloween, the relative 20E titer and 6 20E signaling genes, whereas enhanced the transcription of 3 JH signaling genes. Moreover, silence of Hvcyp303a1 lowered chitin content and the mRNA levels of 2 chitin biosynthesis genes. 20E ingestion by Hvcyp303a1 RNAi larvae completely restored the expression of 20E cascade, JH signaling and chitin biosynthesis genes, partially alleviated negative impacts on chitin amounts, cuticle thickness, foliage consumption, larval growth, pupation and eclosion. Therefore, CYP303A1 facilitates ecdysteroidogenesis. The findings show that dscyp303a1 is a potential RNAi-based strategy for managing H. vigintioctopunctata.