Clonality and host selection in the wheat pathogenic fungus Puccinia triticina
Clonality and host selection in the wheat pathogenic fungus Puccinia triticina
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DOI：
10.1016/j.fgb.2007.02.006
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发表时间：
2007-06-01
影响因子：
3
通讯作者：
Lannou, Christian
中科院分区：
文献类型：
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作者：
Goyeau, Henriette;Halkett, Fabien;Lannou, Christian
小麦叶锈菌（小麦叶锈病的病因）的克隆繁殖长期以来一直被假设，但从未得到证实。使用群体遗传学方法和微卫星标记，我们分析了这种真菌在基因组组织的每个水平上的遗传多样性。采样包括来自在两个携带特定抗性基因的品种上生长的两个田间种群的分离株，并由代表从国家调查中确定的主要致病型的分离株完成。对于这两个品种，群体根据其基因型和致病型的分布而分化。重复基因型的比例很高，并且存在显着的连锁不平衡和 FIS 的强烈负值。这三个因素，尤其是杂合子过多，有力地支持了高克隆繁殖率的假设。每种致病型都与独特的多位点基因型相匹配，但少数分离株除外，这些分离株被认为是显性基因型的突变体。我们讨论了致病型和基因型之间的密切关系，这是克隆繁殖与宿主品种施加的强烈选择相结合的结果。 (c) 2007 Elsevier Inc. 保留所有权利。
Clonal reproduction in Puccinia triticina, the cause of wheat leaf rust, has long been hypothesized but has never been demonstrated. Using a population genetics approach and microsatellite markers, we analysed genetic diversity of this fungus at each level of genome organisation. Sampling included isolates from two field populations growing on two cultivars carrying specific resistance genes, completed with isolates representing the main pathotypes identified from a national survey. For the two cultivars, populations differentiated according to the distribution of their genotypes and pathotypes. There was a high proportion of repeated genotypes, combined with a significant linkage disequilibrium and a strong negative value for FIS. These three factors, especially heterozygote excess, strongly support the hypothesis of a high rate of clonal reproduction. Each pathotype matched a unique multilocus genotype, except for a few isolates, which were taken to be mutants of the dominant genotype. We discussed the strong relationship between pathotypes and genotypes as the consequence of clonal reproduction combined with a strong selection exerted by host cultivars. (c) 2007 Elsevier Inc. All rights reserved.