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

• Main Authors: Xiaorong Xing, Mengwen Yan, Huilin Pang, Fu’an Wu, Jun Wang, Sheng Sheng
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Insects
• Subjects: <i>Meteorus pulchricornis</i>; cytochrome P450s; detoxification; insecticide tolerance
• Online Access: https://www.mdpi.com/2075-4450/12/7/651

With the widespread application of insecticides, parasitoid wasps may also be under risk when exposed to insecticides directly at their free-living stages. The endoparasitoid wasp <i>Meteorus pulchricornis</i> is the predominant natural enemy of many lepidopteran pests, such as <i>Spodoptera litura</i> and <i>Helicoverpa armigera</i>. 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 in <i>M. pulchricornis</i> were identified from a previously constructed transcriptome dataset. These P450 genes belonged to CYP2, -3, and -4, and mitochondrial clans. Subsequently, eight candidate <i>MpulCYPs</i> were 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 of <i>MpulCYPs</i>. To further study the function of P450s, <i>CYP369B3</i> was silenced, and its expression levels of <i>CYP369B3</i> were significantly decreased. Survival analysis indicated that after dsRNA injection, the mortality rate of wasps was significantly increased when <i>M. pulchricornis</i> females 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.