关键词: 亚洲玉米螟, 卵黄原蛋白, 基因克隆, 表达谱, UV-A胁迫

Abstract: 【Aim】 This study aims to explore the effects of UV-A stress on the vitellogenin (Vg) gene expression and fecundity of the Asian corn borer Ostrinia furnacalis by cloning Vg and analyzing its expression pattern. 【Methods】 The full-length cDNA of Vg gene was cloned from O. furnacalis with RT-PCR and RACE techniques and analyzed by bioinformatic methods. The relative expression levels of Vg gene in different developmental stages (egg, 1st-5th instar larva, pupa and adult), different tissues (head, leg, cuticle, ovary, midgut and fat body) of female adults, and female adults of O. furnacalis exposed to UV-A for different time (0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5 and 4 h) were detected by RT-qPCR. The reproduction and development of the F₁ generation of O. furnacalis adults after exposure to UV-A for 0, 1, 2, 3 and 4 h/d were measured. 【Results】 The complete sequence of Vg gene from O. furnacalis was cloned and named as OfVg (GenBank accession no.: MK782978). Its full-length cDNA is 5 760 bp and contains a 5 332 bp open reading frame (ORF), encoding 1 776 amino acids with the predicted molecular weight of 202.10 kD and isoelectric point of 9.06. OfVg contains three functional domains (Vg-N, DUF 1943D and VWD) but has no transmembrane region. The phylogenetic analysis showed that OfVg was most closely related to Vg proteins of other lepidopteran insects. Developmental expression profiling showed that the expression level of OfVg in female adult was significantly higher than those in other developmental stages, reaching the peak in 24 h-old female adult. Tissue expression profiling revealed that OfVg was specifically expressed in the fat body of female adults. UV-A stress induced the expression of OfVg in female adults, with the expression level decreasing firstly and then increasing with the increase of exposure time, reaching the maximum at 3.5 h post exposure to UV-A, and then decreasing abruptly. When the adults were exposed to UV-A for 1, 2 and 3 h/d, their fecundity increased, and the developmental duration of larvae of F₁ generation was prolonged significantly. 【Conclusion】 The expression level of OfVg varies in different developmental stages, different tissues of female adults and female adults of O. furnacalis exposed to UV-A for different time. This study lays a foundation for further studying the effect of UV-A stress on the development and reproduction of O. furnacalis.

Key words: Ostrinia furnacalis, vitellogenin, gene cloning, expression profile, UV-A stress