Population structure of Mycosphaerella graminicola:: From lesions to continents
Population structure of Mycosphaerella graminicola:: From lesions to continents
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DOI：
10.1094/phyto.2002.92.9.946
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发表时间：
2002-09-01
期刊：
影响因子：
3.2
通讯作者：
McDonald, BA
中科院分区：
文献类型：
--
作者：
Linde, CC;Zhan, J;McDonald, BA
利用限制性片段长度多态性标记，在不同的空间尺度上对禾生球腔菌田间种群的遗传结构进行了研究。分层基因多样性分析包括来自7个田间种群的1，098个菌株。空间尺度从毫米到数千公里不等，包括病变内和病变间的比较，区域内和区域间的比较，以及区域和大陆内和区域间的比较。在最小的空间尺度上，微横断面采样被用来确定15个基因型的空间分布中发现的158个菌株从5个单独的病变。每个病变有两到六种不同的基因型，包括五个病变中的四个的两种交配型，但在大多数情况下，病变由一种或两种基因型组成，占据了病变的大部分，其他罕见基因型散布在常见基因型中。大部分（77%）的基因多样性分布在1 - 9平方米的地块内。基因型多样性（GIN）在瑞士，得克萨斯州和以色列领域的领域是高的，从79%到100%的最大可能值。低群体分化表明低G（ST）值的群体之间，这表明相应的高程度的基因流这些群体之间。在最大的空间尺度上，来自瑞士，以色列，俄勒冈州和得克萨斯州的人口进行了比较。这些群体之间的群体分化较低（G（st）= 0.05），群体间的遗传一致性较高。居群间的遗传距离与地理距离呈显著的低度相关（r =-0.47，P = 0.012），表明居群间的基因流和遗传漂变可能尚未达到平衡。区域层面上的基因流动可以通过实施战略来减少，例如改进残茬管理，最大限度地减少子囊孢子的产生。区域一级高水平基因流动的可能性表明，使杀真菌剂抗性或抗性基因崩溃的突变等位基因的区域传播存在重大的潜在风险。
The genetic structure of field populations of Mycosphaerella graminicola was determined across a hierarchy of spatial scales using restriction fragment length polymorphism markers. The hierarchical gene diversity analysis included 1,098 isolates from seven field populations. Spatial scales ranged from millimeters to thousands of kilometers, including comparisons within and among lesions, within and among fields, and within and among regions and continents. At the smallest spatial scale, microtransect sampling was used to determine the spatial distribution of 15 genotypes found among 158 isolates sampled from five individual lesions. Each lesion had two to six different genotypes including both mating types in four of the five lesions, but in most cases a lesion was composed of one or two genotypes that occupied the majority of the lesion, with other rare genotypes interspersed among the common genotypes. The majority (77%) of gene diversity was distributed within plots ranging from approximate to1 to 9 m(2) in size. Genotype diversity (GIN) within fields for the Swiss, Texas, and Israeli fields was high, ranging from 79 to 100% of maximum possible values. Low population differentiation was indicated by the low G(ST) values among populations, suggesting a corresponding high degree of gene flow among these populations. At the largest spatial scale, populations from Switzerland, Israel, Oregon, and Texas were compared. Population differentiation among these populations was low (G(st) = 0.05), and genetic identity between populations was high. A low but significant correlation between genetic and geographic distance among populations was found (r = -0.47, P = 0.012), suggesting that these populations probably have not reached an equilibrium between gene flow and genetic drift. Gene flow on a regional level can be reduced by implementing strategies, such as improved stubble management that minimize the production of ascospores. The possibility of high levels of gene flow on a regional level indicates a significant potential risk for the regional spread of mutant alleles that enable fungicide resistance or the breakdown of resistance genes.