草地贪夜蛾Myo基因调控变态发育分子机制的研究

昆虫的生长发育主要有保幼激素和蜕皮激素协同调控。截止目前，昆虫生长发育的分子调控机制并不十分明确。当昆虫生长到临界尺寸的时候，变态初始因子开始触发变态发育的发生。但是昆虫的变态初始因子一直还没有被找到。申请人敲除了草地贪夜蛾保幼激素受体Met和转录调控因子Kr-h1，发现突变体表现为一样的早熟蛹形态，说明没有了保幼激素的抑制，幼虫提前化蛹。定量PCR测定发现TGF-beta通路配体myoglianin (Myo)基因在早熟蛹形态出现前开始高表达，而在野生品系中Myo基因也是在化蛹前开始高表达，暗示Myo在鳞翅目昆虫变态发育中发挥关键作用。本项目拟利用CRISPR/Cas9敲除Myo基因，结合转录组测序分析Myo的互作基因，揭示Myo调控变态发育的机制。本研究将加深鳞翅目昆虫变态发育调控机制的理论认识，同时为基于昆虫生长调节剂的绿色高效防控策略提供科学依据。

Insect metamorphosis is regulated by juvenile hormone (JH) and 20-hydroxyecdysone (20E). But the mechanism of metamorphosis is still not very clear. Once the insect reach threshold size, the metamorphosis initiate factor (MIF) starts triggering the metamorphosis, while the MIF of the insect is still not found yet. Based on our current study, when the JH receptor-methoprene tolerate gene was knocked out by CRISPR/Cas9, the mutants displayed precious metamorphosis in the later larval stage; and even knocked out transcription factor- krüppel homology 1 gene, the mutants also showed similar precious metamorphosis phenotype. Quantitative PCR analysis found the ligand myoglianin (Myo) of the TGF-beta pathway increased before the mutants showed precious metamorphosis. And in the wild type strain, Myo starts to express prior to metamorphosis. According to the above results, Myo played a key role in regulating the metamorphosis. In order to study the function of Myo during the metamorphosis, CRISPR/Cas9 will be applied to knock out Myo in Spodopter frugiperda, and interaction genes of Myo will be figured out by transcriptome sequencing. This study will not only increase the understanding of metamorphosis but also improve the application of insect growth regulators in pest control.