First and second authors: Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz, Iran; third and fourth authors: Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park 16802; and fifth and sixth authors: School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, New York 14853.
Phytopathology. 2018 Jun;108(6):780-788. doi: 10.1094/PHYTO-11-17-0360-R. Epub 2018 Apr 16.
Verticillium dahliae is a plant pathogenic fungus that reproduces asexually and its population structure is highly clonal. In the present study, 78 V. dahliae isolates from Iran were genotyped for mating type, single nucleotide polymorphisms (SNPs), and microsatellites to assign them to clonal lineages and to determine population genetic structure in Iran. The mating type of all isolates was MAT1-2. Based on neighbor-joining analysis and minimum spanning networks constructed from SNPs and microsatellite genotypes, respectively, all but four isolates were assigned to lineage 2B; four isolates were assigned to lineage 4B. The inferred coalescent genealogy of isolates in lineage 2B showed a clear divergence into two clades that corresponded to geographic origin and host. Haplotypes of cotton and pistachio isolates sampled from central Iran were in one clade, and those of isolates from Prunus spp. sampled from northwestern Iran were in the other. The strong divergence in haplotypes between the two clades suggests that there were at least two separate introductions of lineage 2B to different parts of Iran. Given the history of cotton and pistachio cultivation and Verticillium wilt in Iran, these results are consistent with the hypothesis that cotton was historically a likely source inoculum causing Verticillium wilt in pistachio.
大丽轮枝菌是一种植物病原真菌，它进行无性繁殖，种群结构高度克隆。本研究对来自伊朗的 78 个大丽轮枝菌分离株进行了交配型、单核苷酸多态性 (SNP) 和微卫星分析，以确定其克隆谱系并确定伊朗的种群遗传结构。所有分离株的交配型均为 MAT1-2。基于 SNP 和微卫星基因型构建的邻接聚类分析和最小跨度网络，除了 4 个分离株外，其余分离株均被分配到谱系 2B；4 个分离株被分配到谱系 4B。谱系 2B 中分离株的推断的合并基因树清楚地分为两个分支，这两个分支与地理起源和宿主相对应。从中部伊朗采集的棉花和开心果分离株的单倍型在一个分支中，而从西北部伊朗采集的李属植物分离株的单倍型在另一个分支中。两个分支之间单倍型的强烈分歧表明，至少有两个谱系 2B 分别传入伊朗的不同地区。考虑到棉花和开心果的种植历史以及伊朗的黄萎病，这些结果与棉花历史上可能是引起开心果黄萎病的接种体来源的假设一致。
