Race Dynamics, Diversity, and Virulence Evolution in Puccinia striiformis f. sp tritici, the Causal Agent of Wheat Stripe Rust in China from 2003 to 2007
Race Dynamics, Diversity, and Virulence Evolution in Puccinia striiformis f. sp tritici, the Causal Agent of Wheat Stripe Rust in China from 2003 to 2007
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DOI：
10.1094/pdis-93-11-1093
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发表时间：
2009-11-01
期刊：
影响因子：
4.5
通讯作者：
Wang, B. T.
中科院分区：
文献类型：
--
作者：
Chen, W. Q.;Wu, L. R.;Wang, B. T.
小麦条锈病是小麦最具破坏性的叶面病害。分析了病原菌种群在时空上的毒力演化、复杂性、表型动态和多样性。从2003 ~ 2007年在中国15个省份小麦产区收集的4,714株条锈病分离株中，共鉴定出41个小种。这些小种是基于对19种不同宿主基因型的无毒/毒力模式。中国条锈病种群多样性高，毒力结构复杂。利用相对香农指数进行的比较表明，尽管随着时间的推移，国家倾向于减少多样性，但在不同年份和不同地区的病原体种群中，种族的丰富度和均匀性存在一些差异。本研究记录的主要毒力变化是CYR33（中国黄锈病33）对YrSu具有毒力的频率显著增加，不同地区的小麦锈病分离株在小种组成、分布频率和多样性上存在差异。西北和西南地区主要小种分布不均匀，多样性较黄淮海地区大，说明病原菌的远距离迁移是从一个或多个过夏区向东迁移到越冬区。这支持了甘肃南部和四川西北部构成“毒力起源中心”的假设。条锈菌对寄主抗性的毒力或无毒力突变可能是新毒型发生的根本原因。某些种族随后的优势将随着寄生适应度和通过大规模培育具有匹配抗性基因的品种而选择的机会而变化。讨论了病原菌种群中毒力变异和多样性的起源中心的含义以及限制毒力进化的替代策略。
Stripe (or yellow) rust caused by Puccinia striiformis f. sp. tritici is the most destructive foliar disease of wheat in China. The pathogen populations were analyzed for virulence evolution, complexity, phenotypic dynamics, and diversity on temporal and spatial bases. A total of 41 races were identified and characterized from 4,7 14 stripe rust isolates collected during 2003 through 2007 from wheat growing areas in 15 provinces in China. The races were based on avirulence/virulence patterns to 19 differential host genotypes. Chinese stripe rust population exhibited high diversity with a complex virulence structure. Comparisons using the relative Shannon's index indicated that some differences in the richness and evenness of races were present in pathogen populations within years and between regions despite a national tendency to reduced diversity over time. A noticeably increased frequency of race CYR33 (Chinese yellow rust 33) with virulence for YrSu was the major virulence change recorded in this study compared to the results on an annual basis, Isolates of Puccinia striiformis f. sp. tritici from different regions showed differences in the composition of races, distribution frequency, and diversity. The uneven distribution of major races and comparatively greater diversity in the Northwest and Southwest regions than that in the Huang-Huai-Hai region suggest that long-distance migrations of the pathogen Occur from one or more over-summering areas eastward into over-wintering areas. This supports the hypothesis that southern Gansu and northwestern Sichuan comprises a "center of origin for virulence". Mutation of virulence or avirulence for host resistance in the stripe rust fungus may be the basic cause of the occurrence of new virulent types. The subsequent dominance of certain races will vary with parasitic fitness and the opportunities to be selected through large-scale cultivation of varieties with matching resistance genes. Implications of the center of origin for virulence variation and diversity in the pathogen population and an alternative strategy for limiting virulence evolution are discussed.