Population structure and diversity in sexual and asexual populations of the pathogenic fungus Melampsora lini
Population structure and diversity in sexual and asexual populations of the pathogenic fungus Melampsora lini
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DOI：
10.1111/j.1365-294x.2008.03843.x
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发表时间：
2008-07-01
影响因子：
4.9
通讯作者：
Linde, Celeste C.
中科院分区：
文献类型：
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作者：
Barrett, Luke G.;Thrall, Peter H.;Linde, Celeste C.
许多病原体都不同程度地经历了有性繁殖和无性繁殖，但不同生殖策略的生态、遗传和进化后果仍然知之甚少。本文利用扩增片段长度多态性(AFLP)标记、两个致病基因和致病力表型变异，研究了植物病原菌Melampsora lini在其寄主边缘亚麻上的野生种群遗传结构。在澳大利亚，林氏支原体以两个遗传和地理上不同的谱系(AA和AB)出现，其中一个是完全无性的(AB)，另一个能够克隆和有性繁殖(AA)。为了量化这些不同生活史的遗传和进化后果，我们在两个生物地理区域中的每个区域抽样了五个种群。对275个分离物的AFLP数据分析显示，这两个不同谱系的地理分布很大程度上是分离的，谱系内的遗传多样性较低，每个地区内种群之间的遗传结构很强。我们还检测到了AVR基因和毒力表型在不同种群之间的显著差异，尽管这些值总体上低于AFLP标记获得的值。此外，属于AA谱系的菌株总体上比AB谱系的菌株具有显著更高的基因和表型多样性。这些结果说明了繁殖方式和地理结构在种群毒力多样性的产生和维持中的重要作用。
Many pathogens undergo both sexual and asexual reproduction to varying degrees, yet the ecological, genetic and evolutionary consequences of different reproductive strategies remain poorly understood. Here we investigate the population genetic structure of wild populations of the plant pathogen Melampsora lini on its host Linum marginale, using amplified fragment length polymorphism (AFLP) markers, two genes underlying pathogen virulence, and phenotypic variation in virulence. In Australia, M. lini occurs as two genetically and geographically divergent lineages (AA and AB), one of which is completely asexual (AB), and the other able to reproduce both clonally and sexually (AA). To quantify the genetic and evolutionary consequences of these different life histories, we sampled five populations in each of two biogeographical regions. Analysis of AFLP data obtained for 275 isolates revealed largely disjunct geographical distributions for the two different lineages, low genetic diversity within lineages, and strong genetic structure among populations within each region. We also detected significant divergence among populations for both Avr genes and virulence phenotypes, although generally these values were lower than those obtained with AFLP markers. Furthermore, isolates belonging to lineage AA collectively harboured significantly higher genotypic and phenotypic diversity than lineage AB isolates. Together these results illustrate the important roles of reproductive modes and geographical structure in the generation and maintenance of virulence diversity in populations of M. lini.