Expression of the cytochrome P450 gene AcCYP6CY14 and its role in imidacloprid resistance in Aphis citricola
Author of the article:FAN Ji-Qiao1, 2** HAN Peng-Fei1, 3 GAO Yue1, 2 LIU Zhong-Fang1, 2 ZHANG Peng-Jiu1, 2 YANG Jin1,
Author's Workplace：(1. Shanxi Key Laboratory of Integrated Pest Management in Agriculture, Taiyuan 030031, China; 2. Institute of Plant Protection, Shanxi Academy of Agricultural Sciences, Taiyuan 030031, China; 3. Institute of Applied Biology, Shanxi University, Taiyuan 030006, China
Key Words：Aphis citricola; imidacloprid; cytochrome P450; RNA interference; metabolic detoxification
Abstract：
[Objectives] To study the developmental expression of the cytochrome P450 gene AcCYP6CY14 and its role in imidacloprid resistance in Aphis citricola. [Methods] Partial cDNA sequences of AcCYP6CY14 were obtained by searching the transcriptome database of A. citricola. Full-length cDNA of the target gene was cloned using RT-PCR, and its relative expression in different developmental stages measured using real-time quantitative PCR (RT-qPCR). The 3rd instar of A. citricola was chosen for an induction experiment using the insect-soaking method and the relative expression of AcCYP6CY14 was detected by RT-qPCR after exposing insects to imidacloprid for different periods of time. The target gene was silenced using RNA interference (RNAi) technology by feeding nymphs dsRNA, and the susceptibility of the nymphs to imidacloprid was assessed. [Results] The length of the full-length cDNA sequence of AcCYP6CY14 was 1 542 bp, encoding 513 amino acids (GenBank accession No.: MH717248). AcCYP6CY14 was expressed in all developmental stages of A. citricola but was highest in 3rd instar nymphs. After exposure to an LC30 dose of imidacloprid for 12 h, the relative expression of the AcCYP6CY14 was significantly higher than that of the control group. Feeding nymphs dsAcCYP6CY14 for 24 h significantly decreased transcripts of AcCYP6CY14 when nymphs were transferred to tender stems for 24, 48 and 72 h. A. citricola became more sensitive to imidacloprid (P < 0.01) when AcCYP6CY14 was silenced after which mortality increased by 65.2%. [Conclusion] The full-length cDNA sequence of AcCYP6CY14 was cloned and was found to be expressed in all developmental stages of A. citricola. Expression was highest in 3rd instar nymphs. This gene may play a role in imidacloprid resistance in A. citricola.