摘要
昆虫卵黄发生及其内分泌调控机理一直是昆虫生殖生理学的研究热点。由保幼激素代谢通路关键分子介导的调控系统是影响昆虫卵黄发生的关键途径。研究激素代谢通路关键调控因子的功能将为明确生殖调控机理提供理论依据。保幼激素酯酶(juvenile hormone esterase,JHE)是降解昆虫体内保幼激素的关键酶之一,具有调控昆虫发育、变态和生殖等功能。本实验以烟粉虱Bemisia tabaci MED隐种为研究对象,采用反转录PCR(reverse transcription PCR,RT-PCR)和cDNA末端快速扩增PCR(rapid amplification of cDNA ends PCR,RACE-PCR)技术克隆获得编码552个氨基酸的烟粉虱MED隐种保幼激素酯酶基因的部分cDNA序列,将其命名为Btjhe(GenBank登录号为KC422259)。同源序列比对发现,该基因与菜叶蜂Athalia rosae、西方蜜蜂Apis mellifera的保幼激素酯酶基因推导的氨基酸一致性较高,且具有昆虫保幼激素酯酶共有的5个氨基酸保守模块,其中包括对保幼激素酯酶活性起关键作用的长疏水结合域GxSxG。由此推测,Btjhe为烟粉虱MED隐种的保幼激素酯酶基因,其编码蛋白参与烟粉虱体内保幼激素的特异性降解。实时荧光定量PCR检测结果表明,Btjhe在烟粉虱若虫、成虫阶段都有表达,在成虫阶段表达量较高,且在羽化后11d达到峰值,其表达模式与卵黄原蛋白基因(vg)类似。本研究结果为明确烟粉虱的生殖调控机理奠定基础。
Insect reproduction physiology mainly focuses on the endocrine regulation mechanism of viteUogenesis. ViteUogenesis is regulated by the juvenile hormone metabolic pathway in most insects. Analysis of the function of the key regulation elements in hormone metabolic pathway will illustrate the reproductive regulation mechanism. Juvenile hormone esterase （JHE） plays an important role in insect juvenile hormone degradation, development, metamorphosis and reproduction. We cloned partial eDNA sequence of juvenile hormone esterase gene by RT-PCR and RACE-PCR from the whitefly Bemisia tabaci MED, which was named as Btjhe and deposited in GenBank under the accession no. KC422259, encoding 552 amino acids. Btjhe showed high identity in the deduced amino acid sequence with JHE genes in Athalia rosae and Apis mellifera. The deduced amino acid sequence of Btjhe contains five conserved motifs identified in JHEs of other insect species, including a long hydrophobic binding pocket GxSxG motif that is required for the key enzymatic activity of JHE proteins. Thus, Btjhe is inferred to code juvenile hormone esterases in B. tabaci MED. The mRNA expression level of Btjhe was detected in nymphs and adults at different developmental stages by real-time quantitative PCR. The expression level was higher in adults than in nymphs and reached the peak at 11 d after eclosion. Dynamics of the mRNA expression level of Btjhe was similar with that of the vitellogenin gene （vg）. The results provide insights into the molecular and physiological mechanisms underlying the regulation of whitefly reproduction.
出处
《昆虫学报》
CAS
CSCD
北大核心
2013年第3期234-242,共9页
Acta Entomologica Sinica
基金
国家重点基础研究发展规划项目(2009CB119200)
国家自然科学基金青年基金项目(31101674)
