Cloning of the vitellogenin receptor gene and its expression under UV-A stress in Ostrinia furnacalis
Author of the article:LIU Fang；MENG Jian-Yu；SU Li；ZHANG Chang-Yu
Author's Workplace：1. Guizhou Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Institute of Entomology, Guizhou University, Guiyang 550025, China; 2. Guizhou Tobacco Science Research Institute, Guiyang 550081, China
Key Words：Ostrinia furnacalis; vitellogenin receptor; UV-A stress; RT-qPCR
Abstract：
[Objectives] To explore the effects of UV-A stress on the expression of the vitellogenin receptor (VgR) gene in the Asian corn borer Ostrinia furnacalis. [Methods] The full-length sequence of the VgR gene was cloned from O. furnacalis with reverse transcription PCR（RT-PCR）and the rapid amplification of cDNA ends（RACE）technique and its characteristics analyzed using bioinformatics methods. Real-time quantitative PCR (RT-qPCR) technology was used to detect the expression of the VgR gene in different developmental stages (eggs, 1st-5th instar larvae, pupae and adults), different tissues of female adults (head, foot, cuticle, ovary, midgut and fat body), and in female adults exposed to UV-A for different periods of time (0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4 and 4.5 h). [Results] The complete VgR gene was cloned from O. furnacalis and named OfVgR (GenBank login number: MN058042). Its full-length cDNA was 6 289 bp in length with a 5 490 bp open reading frame (ORF) encoding a 205.27 ku protein with 1 829 amino acids, including a putative 31-amino-acid signal peptide at the N-terminus. OfVgR contains conserved domains, including two ligand-binding domains (LBD), two EGF-precursor homology domains (EGFP), a transmembrane domain (TMD) and a cytoplasmic domain. A phylogenic tree indicates that the protein is closely related to the VgR proteins of other Lepidoptera. RT-qPCR results revealed that OfVgR is expressed in all developmental stages of O. furnacalis, with higher expression in eggs and female adults. Expression was highest in female adults 24 h after eclosion. Expression of OfVgR in different adult female tissues was highest in ovary. OfVgR expression first decreased, increased, then decreased with increased duration of UV-A exposure, with peak expression occurring after 3.0 h exposure. [Conclusion] Expression of OfVgR differs in different developmental stages and adult female tissues and expression in female adults is affected by the duration of exposure to UV-A. These findings lay a foundation for investigating the molecular effects of UV-A stress on the reproduction of O. furnacalis.