麦红吸浆虫蜕皮激素受体(EcR)基因的克隆与表达分析

Molecular cloning and expression analysis of an ecdysone receptor (EcR) gene in the wheat midge,Sitodiplosis mosellana (Diptera:Cecidomyiidae)

为了研究蜕皮激素受体(EcR)在麦红吸浆虫Sitodiplosis mosellana(Géhin)滞育活动中的作用,利用RT-PCR和RACE技术克隆得到了麦红吸浆虫蜕皮激素受体基因cDNA全长,并通过Real-time quantitative PCR研究了其表达情况。该cDNA全长序列被命名为SmEcR(GenBank登录号:KC491135),其开放阅读框长1386bp,编码461个氨基酸残基。其蛋白预测分子量52.90kD,理论等电点6.24。该蛋白与其他已报道的昆虫EcR蛋白具有很高的同源性,其中与迟眼蕈蚊Bradysia coprophila中相应蛋白的氨基酸序列一致性高达92%。SmEcR在麦红吸浆虫不同滞育时期和不同虫态中均有表达,且在不同滞育时期、不同虫态中的表达量差异很大。在滞育不同时期以11月表达量最高,12月表达量最低;在不同虫态以麦穗幼虫中的表达量较低,而成虫中的表达水平很高。本研究为进一步明确SmEcR在麦红吸浆虫滞育调控中的作用奠定了基础。

In order to study the function of ecdysone receptor in the diapause of Sitodiplosis mosellana, the full length cDNA sequence of an ecdysone receptor gene was amplified by using reverse transcription-polymerase chain reaction （RT-PCR） and rapid amplification of cDNA ends （RACE）, and the expression of the EcR gene was analyzed using real-time quantitative PCR （qPCR）. The full-length cDNA sequence was named as SmEcR （GenBank accession number： KC491135）. Its open reading frame （ORF） is 1 386 bp in length, encoding a 461 amino acid protein, with a calculated molecular weight of 52.90 kD and the theoretical isoelectric point of 6.24. Multiple sequence alignment revealed that the deduced amino acid sequence of SmEcR has high identity with EcRs from other insect species, especially with that of Bradysia coprophila （92%）. Real-time quantitative PCR showed that SmEcR transcripts were detected in all diapause and developmental stages. The expression of SmEcR was significantly different among different diapause stages, reaching the highest level in November and the lowest level in December. The larvae collected from wheat heads had a lower expression level of SmEcR while the adults had the highest SmEcR transcripts. This study lays the foundation for the further functional study of SmEcR in diapause regulation in S. mosellana.