中国云南-南亚小麦条锈菌群体遗传结构研究

Wheat stripe rust（Puccinia striiformis f. sp. tritici, Pst）is an important air dispersed disease which threatens wheat security severely. The strategy for controlling the disease is both headstream management and migration route cutting of Pst, and this relies on the research of origin and migration of Pst. The recent research suggested the Himalayan (Pakistan and Nepal) and neighboring regions (Gansu, China) as the putative center of origin for Pst worldwide. Our research, however, indicated that Pst in Gansu originated from Yunnan, and Yunnan was the origin center of Pst in China. Then, whether Yunnan is the center of Pst worldwide or originated from Pakistan or Nepal? And what is the relationship among the Pst populations of Yunnan, South Asia such as Pakistan and Nepal, as well as the origin center of wheat such as Iran ? These issues need to be researched urgently. The research results will not only supplement and perfect the theory of migration of Pst in the world, but also guide on the management of stripe rust in South Asia and China. In this study, we will carry out analysis of virulence genes and frequency of Pst, to research its temporal and spatial dynamic, by using a set of near-isogenic lines as differentials. Furthermore, carry out SNP analysis of Pst population by using house-keeping genes such as Cdc2, Ef-1α and Mapk1 etc. of Pst. To compare research on Pst populations among Yunnan, Pakistan, Nepal and Iran on traditional and molecular level, so as to reveal the origin, evolution and migration of Pst in these regions.

条锈病是严重威胁小麦安全生产的重大气传病害，源头治理及切断传播路线是治理的重要策略，该策略依赖于条锈菌起源及传播的研究。最近研究建议，喜马拉雅（巴基斯坦和尼泊尔）及临近地区（中国甘肃）为世界小麦条锈菌的起源中心。而我们的研究表明甘肃的条锈菌起源于云南，云南为中国小麦条锈菌的初菌源地。云南是否为世界小麦条锈菌的起源中心，还是来源于巴基斯坦或尼泊尔？云南和巴基斯坦、尼泊尔等南亚国家及小麦起源地如伊朗的条锈菌群体是何种关系？急待研究。研究结果将补充和完善世界小麦条锈菌传播理论，指导南亚及中国小麦条锈病的治理。本项目拟采用一套近等基因系鉴别寄主，进行条锈菌毒性基因及其频率分析，研究其时空动态；并采用条锈菌看家基因Cdc2, Ef-1α和Mapk1等，进行条锈菌群体的SNP分析。从传统及分子水平，比较研究云南与巴基斯坦、尼泊尔及伊朗条锈菌群体结构，揭示条锈菌在该地区的起源、进化及传播。

条锈病是世界上最重要的小麦病害，Ali等 (2014) 研究认为喜马拉雅及临近地区（巴基斯坦、尼泊尔和中国）为世界小麦条锈菌的起源中心，伊朗被广泛承认为普通小麦的起源地。云南毗邻喜马拉雅地区，生境复杂，是中国小麦条锈病的重要流行区之一。本项目从病菌毒性及分子水平对比研究了云南与巴基斯坦、尼泊尔及伊朗小麦条锈菌群体结构。2016-2019年采集了云南、巴基斯坦、尼泊尔及伊朗小麦条锈病热点地区的标样1318份，完成了499份标样的毒性鉴定，鉴定出226个小种。结果表明云南和巴基斯坦、尼泊尔、伊朗条锈菌毒性组成差异较大，优势小种互不相同，云南为550273和550073，巴基斯坦为574212, 574213, 574232, 474232, 474233和434232，尼泊尔为561262，伊朗无优势小种。小种丰富度（Margalef 指数），尼泊尔最高，为0.9349；云南、巴基斯坦、伊朗依次为0.9109、0.8044和0.5315。抗条锈基因Yr5, Yr10, Yr15, Yr24和YrTr1当前在云南、巴基斯坦、尼泊尔、伊朗和埃及一致表现有效，而Yr1,Yr9,Yr17,Yr32,YrSP和YrTye (Yr76)在不同地点抗感表现不一致。采用中国鉴别寄主对云南52份标样的小种鉴定表明，优势小种为CYR34和CYR32，频率分别为19.23%和9.62%。采用Cdc2, Mapk1, Hsp, Uba及Ubc等5个看家基因的连接基因，对云南、四川、尼泊尔和伊朗共316份菌样的分子群体结构分析表明，四个地点单倍型多样性都很高，为0.988~1.000。核苷酸多样性为0.00302~0.00727，尼泊尔最高，伊朗最低。群体变异率为0.00302~0.01043，尼泊尔最高，云南次之，为0.00853，伊朗最低。重组事件云南最高，为21，尼泊尔为8，伊朗未检测到。祖先单倍型来自云南2017年的菌株，其比同年采自尼泊尔、伊朗和2016年来自四川的古老。四个群体相比较，尼泊尔群体有较高的遗传多样性及群体变异率，而云南群体有较高的重组事件和较古老的单倍型。项目研究结果可指导云南、南亚及中东的小麦条锈病治理及抗病基因合理布局。项目发表国际期刊论文2篇，国内核心期刊论文3篇。获云南省科技进步一等奖1项。指导2名外籍博士完成科技部国际杰青计划。