内源性转座子与二化螟种群遗传多样性的关系研究

The rice stem borer (Chilo suppressalis walker) is a highly adaptive non-migratory pest. C. suppressalis is wide distribution, omnivorous, genetic diversity, and can quickly adapt to different pesticides and cultivation environment. In the production, C. suppressalis has the periodic large outbreak. Transposon is an important part of the genomes, also is the important power of host evolution. This project is based on the C. suppressalis endogenous transposon, then analysis of the relationships between transposons and C. suppressalis genetic diversity; reveal the function of transposable elements in the evolution of population and environmental adaptation, and analysis of the C. suppressalis population genetic diversity of formation mechanism. Based on the C. suppressalis EST data, we have obtained three kinds of rice stem borer of transposon sequences. Then through the analysis of the genetic variation of transposon sequence, the investigation of a specific transposon insertion locations, and IRAP, REMAP analysis, to comprehensive study of transposable element and the rice stem borer population genetic diversity, and to explore the formation mechanism in the genetic diversity of C. suppressalis. Through the implementation of this project, so that we have a full understanding of the structural characteristics of the rice stem borer endogenous transposon, and understanding the relationship between transposon and C. suppressalis genetic diversity, and recognize the important mechanism of genetic diversity formation in rice stem borer. Also to reveal the mechanisms of genetic adaptation of C. suppressalis, and to provide theoretical guidance for the integrated control of rice stem borer.

二化螟是一种适应性极强的非迁飞害虫，分布范围广，食性多样，遗传多样性丰富，能较快地适应不同的杀虫剂和耕作栽培环境，在生产上形成周期性的大暴发。转座子是宿主基因组的重要组成部分，也是宿主进化的重要动力。本研究在已获得的二化螟3种内源性转座子的基础上，利用这类生物进化的重要内源动力因子，通过对二化螟不同种群体内转座子序列的遗传变异分析、种群的IRAP、REMAP扩增分析、特定转座子的插入位置调查分析以及转座子插入位置处序列的功能分析，研究二化螟种群的遗传多样性及其形成的分子机制，并认识转座子在二化螟种群进化与环境适应中的功能。通过本项目的实施，探索利用转座子分析害虫生物多样性和适应性微进化的新途径，弄清二化螟内源性转座子的序列结构和遗传进化规律，明确转座子与二化螟种群遗传多样性的关系，认识二化螟遗传多样性形成的内源性机制，为二化螟综合治理提供理论指导。

二化螟为非迁飞性昆虫，分布于多种迥异的生态环境，食性复杂，对于外界环境具有很强的适应性。目前，对于二化螟种群在不同生境中高适应性的遗传机制并不清楚。转座子是宿主基因组的重要组成部分，也是宿主进化的重要动力。为此，本项目通过对二化螟不同地理种群体内转座子序列的遗传变异以及插入位点的多态性分析，试图揭示二化螟种群的遗传多样性及其形成的分子机制，并认识转座子在二化螟种群进化与环境适应中的功能。本项目的主要研究内容包括：二化螟内源性转座子序列的克隆与序列分析；不同地理种群二化螟内源性转座子的序列变异和插入位点的多态性；基于转座子标记的二化螟种群遗传多样性分析。通过本项目的实施，成功克隆到二化螟的多种内源性转座子完整序列，包括piggyBac超家族的两种转座子完整序列，分别命名为CsuPLE和CsuPLE1.1，该类转座子属于DNA型转座子；Gypsy/Ty3超家族的一种完整转座子序列，命名为Csu-Ty3，该转座子属于RNA型转座子；Copia/Ty1超家族的一种转座子序列片段，命名为Csu-Ty1，该转座子属于RNA型转座子。进一步基于转座子在二化螟不同地理种群中的插入位点分析和序列变异分析，发现我国二化螟种群具有共同的祖先，并且长江下游地区是我国二化螟种群的潜在起源地区；此外，二化螟不同地理种群存在一定程度的分化，故对二化螟需因地制宜地采取不同的防控治理措施。