Bautista-Jalón Laura S, Frenkel Omer, Tsror Lahkim Leah, Malcolm Glenna M, Gugino Beth K, Lebiush Sara, Hazanovsky Marina, Milgroom Michael G, Del Mar Jiménez-Gasco María
Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802, U.S.A.
Department of Plant Pathology and Weed Research, Volcani Center, Rishon Lezion 7528809, Israel.
Phytopathology. 2021 Jan;111(1):149-159. doi: 10.1094/PHYTO-06-20-0230-FI. Epub 2020 Dec 11.
is a soilborne fungal pathogen affecting many economically important crops that can also infect weeds and rotational crops with no apparent disease symptoms. The main research goal was to test the hypothesis that populations recovered from asymptomatic rotational crops and weed species are evolutionarily and genetically distinct from symptomatic hosts. We collected isolates from symptomatic and asymptomatic hosts growing in fields with histories of Verticillium wilt of potato in Israel and Pennsylvania (United States), and used genotyping-by-sequencing to analyze the evolutionary history and genetic differentiation between populations of different hosts. A phylogeny inferred from 26,934 single-nucleotide polymorphisms (SNPs) in 126 isolates displayed a highly clonal structure correlated with vegetative compatibility groups, and isolates grouped in lineages 2A, 2B, 4A, and 4B, with 77% of the isolates in lineage 4B. The lineages identified in this study were differentiated by host of origin; we found 2A, 2B, and 4A only in symptomatic hosts but isolates from asymptomatic hosts (weeds, oat, and sorghum) grouped exclusively within lineage 4B, and were genetically indistinguishable from 4B isolates sampled from symptomatic hosts (potato, eggplant, and avocado). Using coalescent analysis of 158 SNPs of lineage 4B, we inferred a genealogy with clades that correlated with geographic origin. In contrast, isolates from asymptomatic and symptomatic hosts shared some of the same haplotypes and were not differentiated. We conclude that asymptomatic weeds and rotational hosts may be potential reservoirs for populations of lineage 4B, which are pathogenic to many cultivated hosts.
是一种土传真菌病原体，影响许多经济上重要的作物，也能感染杂草和轮作作物，且无明显病害症状。主要研究目标是检验这样一个假设：从无症状轮作作物和杂草物种中分离出的种群在进化和遗传上与有症状的寄主不同。我们从以色列和宾夕法尼亚州（美国）有马铃薯黄萎病史的田间生长的有症状和无症状寄主中收集分离株，并使用测序基因分型来分析不同寄主种群之间的进化历史和遗传分化。从126个分离株中的26934个单核苷酸多态性（SNP）推断出的系统发育显示出与营养体亲和群相关的高度克隆结构，分离株分为2A、2B、4A和4B谱系，其中77%的分离株属于4B谱系。本研究中确定的谱系因起源寄主而异；我们仅在有症状的寄主中发现了2A、2B和4A，但无症状寄主（杂草、燕麦和高粱）的分离株仅聚集在4B谱系内，并且在遗传上与从有症状寄主（马铃薯、茄子和鳄梨）中采样的4B分离株无法区分。使用对4B谱系的158个SNP进行的溯祖分析，我们推断出一个与地理起源相关的进化枝谱系。相比之下，无症状和有症状寄主的分离株共享一些相同的单倍型，没有分化。我们得出结论，无症状杂草和轮作寄主可能是4B谱系种群的潜在储存库，该谱系对许多栽培寄主具有致病性。
