黏虫保幼激素环氧水解酶基因MsJHEH2的克隆与生物学功能

保幼激素环氧水解酶（juvenile hormone epoxide hydrolase，JHEH）是调控保幼激素（juvenile hormone，JH）滴度的重要降解酶。本文在黏虫体内克隆得到一条具有EHN环氧水解酶超家族结构域的保幼激素环氧水解酶MsJHEH2基因cDNA序列（GenBank登录号：MT802192），长度1533 bp，开放阅读框（ORF）为1389 bp，编码462个氨基酸，推测分子量和等电点分别为52.42 kDa和7.07。表达模式分析发现，MsJHEH2在黏虫各个龄期与组织中均有表达，其中在蛹期和中肠中表达量最高。RNA干扰处理4龄幼虫6 h后的基因沉默效率最高，为64.86%，此时黏虫体内JH滴度上升为对照的1.58倍。该基因沉默后对黏虫无明显致死作用，但导致其蛹历期延长、羽化率降低。本研究表明MsJHEH2可以通过调节JH含量进而影响黏虫生长发育进程。

Cloning and Biological Functional Analysis of Juvenile Hormone Epoxide Hydrolase Gene MsJHEH2 from Mythimna separata

Juvenile hormone epoxide hydrolase (JHEH) is an important degradation enzyme in the metabolism of juvenile hormone. A cDNA sequence of juvenile hormone epoxide hydrolase MsJHEH2 with EHN epoxyhydrolase superfamily domain (GenBank accession number:MT802192) was cloned from Mythimna separata. The length sequence of MsJHEH2 was 1533 bp with an open reading frame (ORF) of 1389 bp, encoding 462 amino acids. The predicted molecular weight and isoelectric point were 52.42 kDa and 7.07, respectively. The results of mRNA expression pattern showed that MsJHEH2 was expressed at all developmental stages and in all tissues examined, the highest expression levels were found in pupal stage and midguts, respectively. After the 4^th instar larvae were treated with siRNA interference for 6 h, the gene silencing efficiency reached 64.86%, the content of juvenile hormone increased 1.58 fold. Gene inhibition had no significant lethal effect on M. separata, but the pupal duration prolonged and emergence rate decreased significantly. The results indicated that MsJHEH2 affected the growth and development of M. separata by regulating the content of juvenile hormone.