保幼激素在小菜蛾生殖调控中的作用及其分子机理

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae) is the most destructive pest of economically important Brassicea crops. Currently, optimal strategies and tactics are still required in order to effectively control this pest insect with high fecundity. To better understand the effect of reproductive regulation on reproductive potential and adaptability of P. xylostella, we propose to carry out researches from two aspects with the reproduction hormone as a core, including juvenile hormone (JH) synthesis and its functional receptor. The project includes four components: (1) to measure the function of JHAMT in reproductive regulation of P. xylostella, (2) to uncover the function of Met in reproductive regulation of P. xylostella, (3) to screen and identify the interacting protein of Met, and to analyze the function of interacting protein of Met. The ultimate goal of this project is to elaborate the integration of function and molecular mechanism of JH in reproductive regulation, which is helpful for better understanding of the roles of JH in reproductive capacity and adaptive potential to various environments. This proposed project will establish the theoretical foundations of reproductive mechanisms under hormone regulation in P. xylostella, and then screen potential genes or regulatory pathways that can be potentially used for genetic manipulation of the P. xylostella populations subject to varying agroecosystems.

针对世界性的重要害虫小菜蛾仍缺乏直接、安全、有效的控制策略的实际需求，围绕生殖调控决定昆虫生殖潜能与适应性这一科学问题，以激素调控生殖为核心，采用生物化学与分子生物学、蛋白质组学、免疫化学、解剖形态学与实验生物学等方法，从保幼激素（juvenile hormone，JH）的合成以及作用受体两个方面开展研究，重点研究：(1)JH合成关键基因JHAMT在小菜蛾生殖调控中的作用；(2)JH关键受体基因Met在小菜蛾生殖调控中的作用；(3)JH关键受体蛋白Met的互作蛋白筛选、鉴定及功能分析。最后综合分析JH在小菜蛾生殖调控中的作用及其分子机理，明确JH对小菜蛾生殖潜能的影响。项目预期成果可为全面解析激素调控下的小菜蛾生殖过程奠定基础，在实践上有助于筛选控制小菜蛾的潜在靶标，为有效防治和持续控制小菜蛾种群暴发与危害提供创新思路和途径。

小菜蛾是危害十字花科作物的世界性迁飞害虫，强大的生殖能力以及快速发展的抗药性，使其成为田间最难防治的害虫之一。保幼激素JH是调控昆虫生长发育与生殖的主导因子之一，但其介导的分子机制在不同种类昆虫间具有明显差异。本项目首先明确JH参与了小菜蛾蛹期变态与生殖发育过程；JH主要通过调控表皮蛋白基因表达介导小菜蛾蛹期形态建成与变态发育，而在生殖发育过程中，JH主要通过调控卵母细胞与胚胎发育相关基因，如Vg与VgR介导小菜蛾的生殖发育过程。随后明确了Met是JH分子作用的受体基因，小菜蛾基因组中包含两个Met分子，他们具有龄期表达偏好性，抑制Mets基因表达，所产生的生殖调控效应与抑制JH合成一致，均能导致卵巢变小，卵黄沉积减少，成熟卵子数目减少，同时单雌产卵量与孵化率也显著下降。然后筛选获得了Mets蛋白的互作蛋白V-type proton ATPase subunit B-like。最后明确了Vg与VgR基因对于小菜蛾胚胎发育至关重要，敲除Vg与VgR基因虽不会影响单雌产卵量，但会显著降低其孵化率。项目研究结果有助于深入阐明 JH 介导小菜蛾生殖调控的分子机制及信号途径，可为有效挖掘小菜蛾遗传控制新靶标提供新的思路和途径。