Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108.
Phytopathology. 2021 Jul;111(7):1114-1121. doi: 10.1094/PHYTO-08-20-0337-R. Epub 2021 Aug 25.
Bacterial leaf streak (BLS) of wheat, caused by pv. , has been a notable disease in Minnesota wheat fields over the past decade. Potential sources of the pathogen include infested seed and crop debris. Perennial weeds are also considered a possible inoculum source, but no surveys have been conducted to evaluate which pathovars are present on weedy grasses that are common in Minnesota wheat fields. Multilocus sequence analysis (MLSA) of four housekeeping genes (, , , and ) was used to identify 77 strains isolated from six weedy grass species, wheat, and barley in and around naturally infected wheat fields in Minnesota. The MLSA phylogeny identified all strains originating from weedy grass species, except smooth brome, as pv. , whereas strains isolated from smooth brome were determined to be pv. . In planta character states corroborated these identifications on a subset of 41 strains, as all strains from weedy grasses caused water-soaking on wheat and barley in greenhouse assays. Multilocus sequence typing was used to evaluate genetic diversity and revealed that sequence types of pv. originating from weedy grass hosts are similar to those found on wheat. This study identifies both annual and perennial poaceous weeds common in Minnesota that harbor pv. and expands our understanding of the diversity of the pathogen population.
小麦细菌性条斑病（BLS）由 pv. 引起，在过去十年中一直是明尼苏达州小麦田中的一种显著疾病。病原体的潜在来源包括受感染的种子和作物残体。多年生杂草也被认为是可能的接种体来源，但尚未进行调查以评估在明尼苏达州小麦田中常见的杂草草上存在哪些 致病型。对四个管家基因（ 、 、 和 ）的多位点序列分析（MLSA）用于鉴定从明尼苏达州自然感染的小麦田中六个杂草草种、小麦和大麦中分离出的 77 株菌株。MLSA 系统发育树确定了除光滑雀麦以外的所有源自杂草草种的菌株均为 pv. ，而从光滑雀麦中分离出的菌株则被确定为 pv. 。在温室试验中，所有来自杂草草的菌株都会在小麦和大麦上引起水渍，这一植物体内特征状态证实了这些鉴定结果。多位点序列分型用于评估遗传多样性，并表明源自杂草草宿主的 pv. 的序列类型与在小麦上发现的序列类型相似。本研究鉴定了明尼苏达州常见的一年生和多年生禾本科杂草，这些杂草携带 pv. ，并扩展了我们对病原体种群多样性的认识。
