小麦条锈菌高密度遗传图谱的构建及无毒基因的定位

The wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a fungal disease, resulting significant yield loss in severe epidemics. However, the molecular mechanism underlying the rapid change of Pst virulence is still not clear. Studying such molecular mechanism will set solid foundation for disease management. Studies from many pathosystems revealed that avirulence genes (Avr) are key factors in virulence changes. Several Avr have been cloned from other rust fungi through genetic-map based approaches. However, no Avr genes have been positioned at the genome level in the Pst. Genetic mapping Avr will be the first step towards the functional cloning. Previously we have generated a segregating population with 117 progenies using selfing-fertilization for Pst 12-368. In this project, we plant to use whole-genome sequencing technology, QTL approach, and alignment of genetic map to reference genome to construct a high-density genetic map and map the nine Avr genes in wheat stripe rust fungus. This study will provide the first step towards functional cloning of Avr genes, better understanding the molecular basis of virulence variations in the Pst-wheat system.

由条形柄锈菌小麦专化型（Puccinia striiformis f. sp. tritici） 引起的小麦条锈病是制约我国小麦生产的重要病害之一。目前对该病害的毒性变异分子机理尚不清楚，解析毒性变异关键因子可为该病害的防治提供坚实的理论基础。研究表明，植物病原菌中无毒基因是导致毒性变异的关键因子。多个锈菌无毒基因已通过遗传定位的方法被克隆，但在小麦条锈菌中尚无报道。本项目前期采用自交方式构建了小麦条锈菌12-368的117株有性分离群体，经小麦抗条锈单基因系毒性鉴定发现9个无毒基因发生毒性分离。在此基础上，本项目拟通过对该群体全基因组测序开发分子标记，构建小麦条锈菌高密度遗传图谱；利用QTL遗传作图、参考基因组序列比对等方法定位这9个无毒基因，并根据无毒基因结构和功能特点筛选目标基因。本项目为今后无毒基因克隆、深入解析小麦条锈菌毒性变异机制等研究奠定基础。

由条形柄锈菌小麦专化型（Puccinia striiformis f. sp. tritici） 引起的小麦条锈病是制约我国小麦生产的重要病害之一。目前对该病害的毒性变异分子机理尚不清楚，解析毒性变异关键因子可为该病害的防治提供坚实的理论基础。研究表明，植物病原菌中无毒基因是导致毒性变异的关键因子。多个锈菌无毒基因已通过遗传定位的方法被克隆，但在小麦条锈菌中尚无报道。本项目构建了小麦条锈菌12-368的117株有性分离群体，经小麦抗条锈单基因系毒性鉴定发现9个无毒基因发生毒性分离，本项目开发了全基因组分子标记，构建了小麦条锈菌高密度遗传图谱；利用QTL遗传作图、参考基因组序列比对等方法定位了4个无毒基因，并根据无毒基因结构和功能特点筛选目标基因。鉴于目前尚无国内流行生理小种的参考基因组，本项目还组装了高质量的小麦条锈菌CYR34的染色体水平的参考基因组。本项目为今后无毒基因克隆、深入解析小麦条锈菌毒性变异机制等研究奠定基础。