CYP4G8 is responsible for the synthesis of methyl-branched hydrocarbons in the polyphagous caterpillar of Helicoverpa armigera

Yucui Xin; Nan Chen; Yawei Wang; Ruoyao Ni; Hongrui Zhao; Peiqi Yang; Mei Li; Xinghui Qiu

doi:10.1016/j.ibmb.2021.103701

CYP4G8 is responsible for the synthesis of methyl-branched hydrocarbons in the polyphagous caterpillar of Helicoverpa armigera

Insect Biochem Mol Biol. 2022 Jan:140:103701. doi: 10.1016/j.ibmb.2021.103701. Epub 2021 Dec 8.

Authors

Yucui Xin¹, Nan Chen², Yawei Wang¹, Ruoyao Ni¹, Hongrui Zhao³, Peiqi Yang³, Mei Li³, Xinghui Qiu⁴

Affiliations

¹ State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
² Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.
³ State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
⁴ State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China. Electronic address: qiuxh@ioz.ac.cn.

PMID: 34890799
DOI: 10.1016/j.ibmb.2021.103701

Abstract

Insect cuticular hydrocarbons (CHCs) have dual functions as physical barrier and chemical signals. The last step of CHC biosynthesis is known to be catalyzed by cytochrome P450 CYP4G in a number of insects. Until recently, studies on CYP4Gs in the context of functional evolution are rare. In this study, we analyzed sequence similarity and temporal-spatial expression patterns of the five CYP4G genes in the cotton bollworm Helicoverpa armigera, an important agricultural pest and also typical representative of lepidopteran insects. Moreover, the CRISPR/Cas9-induced knockout was used to clarify the roles of the five CYP4Gs in CHC biosynthesis. Temporal-spatial expression patterns revealed that CYP4G8 was highly expressed at all developmental stages and in most tissues examined. Larvae with CYP4G8 knocked out could not produce methyl-branched CHCs and failed to pupate, while larvae with the other four CYP4G genes knocked out (4G1-type-KO) showed no significant changes in their CHC profiles, weight gain and survival. Comparative transcriptomics revealed that knocking out CYP4G8 affected the global gene expression in larvae, especially down-regulated the expression of genes in the fatty acid biosynthetic pathway, while no significant change in 4G1-type-KO transcriptome was observed. These findings indicate that the five members of the CYP4G subfamily have undergone functional divergence: CYP4G8 maintains the essential function in CHC biosynthesis, while the function of the other four CYP4G genes remains unclear. Intriguingly, CYP4G8 has evolved to be a P450 enzyme responsible for the synthesis of larval methyl-branched hydrocarbons. The observation that CYP4G8 knockout is lethal strongly suggest that CYP4G8 may serve as a candidate target for the development of insecticidal agents for the control of cotton bollworms.

Keywords: CRISPR/Cas9; CYP4G; Cuticular hydrocarbons; Functional divergence; Helicoverpa armigera (Lepidoptera: Noctuidae); Transcriptome.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Cytochrome P-450 Enzyme System* / metabolism
Hydrocarbons / metabolism*
Insect Proteins / metabolism
Larva / metabolism
Moths / metabolism
Transcriptome

Substances

Hydrocarbons
Insect Proteins
Cytochrome P-450 Enzyme System