昆虫蜕皮的分子机理及应用

Molecular mechanism of insect molting and application

昆虫蜕皮是一个由PTTH启始的、激素介导的基因序列表达和相互作用的级联反应过程。阐明昆虫蜕皮的分子机理,不仅可以解释发育生物学的科学问题,为害虫控制提供新的思路,还可以从中发现新的可资生产应用的分子。作者通过蛋白质组学方法从棉铃虫Helicoverpa armigera Hubner蜕皮幼虫鉴定到30个差异表达的蛋白质。通过抑制性消减杂交技术,从棉铃虫蜕皮幼虫、变态决定幼虫和5龄取食幼虫鉴定到100个表达序列标签(EST)。证明其中的11个EST在蜕皮或变态时差异表达。通过RT-PCR方法克隆棉铃虫激素接受子3基因,研究该基因在发育中的表达模式。用该基因构建具有绿色荧光蛋白标记和多角体蛋白的基因重组病毒(AcMNPV-GFP-HHR3-Polh)。实验结果表明,AcMNPV-GFPHHR3-Polh病毒可以通过注射或口服感染棉铃虫,导致棉铃虫幼虫非正常蜕皮、生长延缓、半数存活时间下降。该研究显示昆虫蜕皮功能基因在害虫控制中有很好的应用前景。蜕皮功能基因的表达与调控、蜕皮激素介导的信号转导通路、变态过程中组织解体和重建的分子机理、激素调控基因顺序表达的分子机理、变态起始因子、JH受体等是本领域今后的主要研究方向。

Insect molting is a cascade of sequential gene expression and interaction, initiated by PTTH and regulated by hormones. Demonstrating the molecular mechanisms of insect molting may not only interpret the scientific questions in insect development, find new approaches to control pests, but also discover new molecules for use in production. We identified 30 differentially expressed proteins from molting larvae of Helicoverpa armigera Huebner by proteomics study. In addition, we identified 100 expression sequences tags （EST） from molting larvae, metamorphic committed larvae and feeding larvae of H. armigera by suppression subtractive hybridization （SSH） technique. Eleven of these ESTs were proved differentially expressed during larval molting or metamorphosis. By RT-PCR, we cloned H. armigera hormone receptor 3 and investigated its expression patterns during development. The gene was further inserted into AcMNPV to construct a genetically manipulated bacularvirus marked by green fluorescence protein （AcMNPV-GFPHHR3-Polh）. Results showed that AcMNPV-GFPHHR3-Polh may infect H. armigera larvae via ingestion or injection. The virus resulted in abnormal ecdysis, growth retardance and median survival time decrease on the H. armigera larvae. These results suggeste a prospect that the molting related genes can be used in pest control. The expression and regulation of the molting related genes, 20E initiated signal transduction path ways, molecular mechanisms of tissue histolysis and remodeling during metamorphosis, mechanisms of the cascade of gene sequential expression, metamorphosis initiating factor and JH receptor are the major study directions in the future work.