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Involvement of integument‐rich CYP4G19 in hydrocarbon biosynthesis and cuticular penetration resistance in Blattella germanica (L.)
Author(s) -
Chen Nan,
Pei XiaoJin,
Li Sheng,
Fan YongLiang,
Liu TongXian
Publication year - 2020
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.5499
Subject(s) - penetration (warfare) , cuticle (hair) , biology , cytochrome p450 , pyrethroid , arthropod cuticle , monooxygenase , gene knockdown , biochemistry , botany , gene , insect , enzyme , pesticide , anatomy , operations research , engineering , agronomy
BACKGROUND Cuticle penetration plays an important role as a mechanism of insecticide resistance, but the underlying molecular mechanism remains poorly understood. In Blattella germanica , the cytochrome P450 gene, CYP4G19 , is overexpressed in a pyrethroid‐resistant strain. Here, we investigated whether CYP4G19 is involved in the biosynthesis of hydrocarbons and further contributes to cuticular penetration resistance in B. germanica . RESULTS Compared with the susceptible strain, pyrethroid‐resistant cockroaches showed lower cuticular permeability with Eosin Y staining. Removal of epicuticular lipids, mainly nonpolar hydrocarbons, with a hexane wash intensified the cuticular permeability and decreased the resistance index of the resistant strain. CYP4G19 was predominately expressed in the abdominal integument and could be upregulated by desiccation stress or short exposure to beta‐cypermethrin. Overexpression of CYP4G19 in the resistant strain was positively correlated with a higher level of cuticular hydrocarbons (CHCs). RNAi‐mediated knockdown of CYP4G19 significantly decreased its expression and caused a reduction in CHCs. Meanwhile, CYP4G19 suppression resulted in a non‐uniform array of the lipid layer, enhanced cuticle permeability, and compromised insecticide tolerance. CONCLUSION Our findings confirm that CYP4G19 is involved in hydrocarbon production and appears to contribute to hydrocarbon‐based penetration resistance in B. germanica . This study highlights the lipid‐based penetration resistance, advancing our understanding of the molecular mechanism underlying P450‐mediated cuticular penetration resistance in insects. © 2019 Society of Chemical Industry