基于简化基因组测序的不同寄主植物上桃小食心虫种群遗传分化研究

The peach fruit moth (PFM) Carposina sasakii (Lepidoptera: Carposinidae) is one of the major phytophagous pests in orchards. PFMs vary in biology and ecology on different host plants. Revealing the host-associated genetic differentiation is basic to understand the biology and ecology of this moth. Due to the limited number of genetic markers and the sampling design in previous studies, population genetic differentiation of PFMs from different host plants remains controversial. The restriction site associated DNA sequencing (RAD-seq) method can develop genome-wide single nucleotide polymorphisms (SNPs) with high-density, providing an efficient method for detecting low level differentiation between populations and differentiation of specific genes. Based on strict sampling design, this project intends to identify single nucleotide polymorphisms (SNPs) by constructing and sequencing the RAD-seq sequencing libraries on PFMs individuals from different host plants. Secondly, we will scan and isolate neutral and selective SNPs. Based on neutral SNPs, the population genetic structure and gene flow of PFMs among different host plants will be analyzed. By determining the correlation between genetic differentiation and host phenology, host-plant associated genetic differentiation of the PFMs will be analyzed. Thirdly, genomic variations associated with host plants will be scanned and functions of genes that related to the scanned SNPs will be annotated to reveal the mechanism of genetic differentiation of PFMs populations associated with host plants. The results will shed light on the understanding of the underlying mechanism of genetic differentiation of PFMs, contribute to the understanding the occurrence and management of PFM in fields.

桃小食心虫是多种果树上的重要害虫，在不同寄主植物上的发生规律存在明显差异。揭示不同寄主植物上该虫的遗传分化是明确发生规律的基础。受到分子标记数量和采样设计的影响，目前的研究对这一问题尚存在争议。简化基因组测序技术可以开发高密度分子标记，为检测种群间极低水平和特定基因上的遗传分化提供了有效途径。本项目拟在严谨采样设计的基础上，构建不同寄主植物上桃小食心虫的简化基因组文库并进行测序，鉴定基因组层面的SNP分子标记；分离中性和受选择的变异位点，基于中性位点分析不同寄主植物上的种群遗传结构和基因流，明确遗传分化程度与寄主物候期的关系，进而解析该虫在不同寄主植物上的遗传分化规律；筛选与寄主植物相关的受选择位点，并对关联的基因进行功能注释，探讨寄主植物导致该虫种群遗传分化的机制。研究结果对于理解桃小食心虫对不同寄主植物的适应性机制、揭示该虫复杂的发生规律、制定高效防控措施等具有重要的理论和实践意义。

桃小食心虫是苹果、梨、桃等果树上的重要害虫，在不同寄主植物上的发生规律存在明显差异。本项目针对不同寄主植物上桃小食心虫是否存在遗传分化的争议问题，开展了桃小食心虫的发生规律、飞行能力、遗传分化和适应性进化等研究。研究了田间不同寄主植物上该虫的消长规律与滞育率，发现存在较高的寄主间转移的可能性；测定了取食不同寄主植物个体的飞行能力，发现该害虫飞行能力较强，具备转移能力，为桃小食心虫在不同果园间的转移现象提供证据；利用简化基因组测序技术研究了不同寄主果园桃小食心虫的遗传分化，发现不同寄主上桃小食心虫不存在明显的寄主相关性遗传分化；基于简化基因组技术研究我国桃小食心虫不同地区种群，发现该虫起源于我国西南地区，在演化过程中对不同地区产生了强烈的局部适应性，限制了该虫对新环境的适应性。研究结果对于理解桃小食心虫的适应性机制、揭示该虫复杂的发生规律、制定高效防控措施等具有重要的理论和实践意义。