Cytochrome P450s Are Essential for Insecticide Tolerance in the Endoparasitoid Wasp Meteorus pulchricornis (Hymenoptera: Braconidae)

Simple SummaryP450s are involved in the detoxification process in insects; however, less attention has been paid for their roles in parasitoid wasps. Here, we identified 28 P450s from the previous constructed transcriptome dataset ofMeteorus pulchricornisand validated their expression patterns under insecticides exposure. Furthermore, we silencedCYP369B3in adult wasps and demonstrated that the knocking downCYP369B3significantly increased of the mortality of adult wasps when they were exposed to each chemical insecticide, phoxim, cypermethrin, and chlorfenapyr, respectively. The present study provides a theoretical base for functional research on P450 genes in parasitoid wasps.AbstractWith the widespread application of insecticides, parasitoid wasps may also be under risk when exposed to insecticides directly at their free-living stages. The endoparasitoid waspMeteorus pulchricornisis the predominant natural enemy of many lepidopteran pests, such asSpodoptera lituraandHelicoverpa armigera. The cytochrome P450 monooxygenases constitute a ubiquitous and complex superfamily of hydrophobic, haem-containing enzymes. P450s are involved in the detoxification of many xenobiotics. However, their exact roles in the tolerance mechanism in parasitoids toward insecticides has received less attention. Here, 28 P450 genes inM. pulchricorniswere identified from a previously constructed transcriptome dataset. These P450 genes belonged to CYP2, -3, and -4, and mitochondrial clans. Subsequently, eight candidateMpulCYPswere selected from four CYP clans to validate their expression patterns under phoxim, cypermethrin, and chlorfenapyr exposure by qRT-PCR. The results showed that all three insecticides had significant effects on the expression ofMpulCYPs. To further study the function of P450s,CYP369B3was silenced, and its expression levels ofCYP369B3were significantly decreased. Survival analysis indicated that after dsRNA injection, the mortality rate of wasps was significantly increased whenM. pulchricornisfemales were exposed to insecticides compared to control groups. Our findings provide a theoretical base for elucidating the mechanism of insecticide tolerance and promote functional research on P450 genes in parasitoid wasps.Keywords:Meteorus pulchricornis;cytochrome P450s;detoxification;insecticide tolerance