核受体DAF-12介导的松材线虫扩散型幼虫形成机制及抑制剂研究

Bursaphelenchus xylophilus can cause the worldwide quarantine disease, especially cause serious damage in China. The dispersal third-stage is the most important stage during the diffusion, so the extremely urgent task is to study the molecular regulation mechanism in the convertion of different types of Bursaphelenchus xylophilus larvae. Our research group has shown that the nematode could not enter the dispersal stage when steroid hormone exist, while when the steroid hormone was removed, the nematode could enter the dispersal stage. Combined with other research evidence, we suppose that steroid hormone pathway is one of the pathways that mediate the convertion of different types of Bursaphelenchus xylophilus larvae. Previous studies have demonstrated nuclear hormone receptor DAF-12 is the common target of many regulation pathways during the dispersal larvae formation. This research aims to 1) elucidate the mechanism of the steroid hormone pathway on the conversion of propagative larvae to dispersal larvae by in vivo and in vitro studies mediated by nuclear receptor DAF-12, based on the previous study of steroid hormone on the formation and rescue of dispersal third-stage larvae. 2) design and select inhibitors by means of molecular dynamics simulation technology using nuclear receptor DAF-12 as a target, then synthesis and perform analytical tests. All these results will illustrate the mechanism of dispersal larvae formation of Bursaphelenchus xylophilus mediated by nuclear receptor DAF-12; build a platform for studying the developmental biology of Bursaphelenchus xylophilus and provide a new strategy for devising specific control methods.

松材线虫病是世界性的检疫性病害，在我国严重发生。松材线虫繁殖型二龄幼虫转变为扩散型三龄幼虫是实现病害流行的关键环节，研究不同类型幼虫转换的分子调控机制是亟待解决的科学问题之一。项目组前期研究发现，当存在类固醇激素时线虫不能进入扩散型阶段，当去除类固醇激素时可以进入扩散型阶段，结合其它线虫的研究结果，我们推测类固醇激素途径是松材线虫幼虫类型转换的途径之一。前人研究表明，核受体DAF-12是扩散型幼虫形成过程中多种调控途径的共同靶标。本项目拟在前期研究基础上，通过DAF-12与类固醇激素结合的体内体外试验，阐明DAF-12介导的类固醇激素途径对松材线虫幼虫类型转换的调控机制；以DAF-12为靶点，采用分子动力学模拟技术设计和筛选受体抑制剂，并进行合成与测试。研究结果将能够明确核受体DAF-12介导的松材线虫扩散型幼虫形成机制，搭建松材线虫发育生物学研究平台，并为设计特异性的防治措施提供新思路。

松材线虫病是世界性的检疫性病害，在我国严重发生。松材线虫繁殖型二龄幼虫转变为扩散型三龄幼虫是实现病害流行的关键环节，研究不同类型幼虫转换的分子调控机制是亟待解决的科学问题之一。为了明确松材线虫繁殖型和扩散型幼虫转换的机制，本研究根据模式线虫秀丽隐杆线虫的滞育机制，以模式线虫滞育相关基因为基础，从松材线虫中克隆相关基因daf-9和daf-12,并分析基因在不同虫态和环境条件下的表达模式。通过DAF-12与类固醇激素结合的体内体外试验，阐明DAF-12介导的类固醇激素途径是松材线虫幼虫类型转换的重要调控机制；并以DAF-12为靶点，采用分子动力学模拟技术设计和筛选受体抑制剂，并进行合成与测试。研究结果将能够明确核受体DAF-12介导的松材线虫扩散型幼虫形成机制，搭建松材线虫发育生物学研究平台，并为设计特异性的防治措施提供新思路。.同时，除了对以上项目预订内容加以研究，还额外阐明了一种可以捕食松材线虫的滑刃目线虫的形态学和分子分类特征。项目发表SCI收录论文1篇，国内一级期刊1篇，在投SCI论文2篇，申请国家发明专利1项。