Clavijo Felipe, Curland Rebecca D, Croce Valentina, Lapaz María I, Dill-Macky Ruth, Pereyra Silvia, Siri María I
Laboratorio de Microbiología Molecular, Departamento de Biociencias, Facultad de Química, Udelar, 11800, Montevideo, Uruguay.
Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108.
Phytopathology. 2022 Mar;112(3):511-520. doi: 10.1094/PHYTO-06-21-0231-R. Epub 2022 Mar 9.
Bacterial diseases affecting wheat production in Uruguay are an issue of growing concern yet remain largely uninvestigated in the region. Surveys of 61 wheat fields carried out from 2017 to 2019 yielded a regional collection of 63 strains identified by 16S rRNA gene analysis as spp. A real-time PCR protocol with species-specific primers previously reported allowed the identification of 44 strains as , the causal agent of bacterial leaf streak (BLS) in wheat and other cereal crops. Multilocus sequence analysis of four housekeeping genes (, , , and ) revealed that these strains were most closely related to pv. , the pathovar that is most commonly associated with BLS of wheat. Multilocus sequence typing was applied to examine the genetic diversity of strains. Strains were assigned to four different sequence types, three of which were previously reported globally. Additionally, 17 strains not belonging to were obtained from diseased wheat leaves. Phylogenetic analysis showed that these strains are closely related to and clustered together with previously uncharacterized strains isolated from wheat in Minnesota. In planta pathogenicity assays carried out on a BLS-susceptible wheat cultivar showed that pv. strains caused brown necrosis symptoms typical of BLS, whereas non- sp. strains elicited an atypical symptom of dry necrosis. These findings suggest that local wheat fields are affected by pv. and by a new wheat pathogen within the genus.
影响乌拉圭小麦生产的细菌性病害日益受到关注，但该地区对此仍缺乏充分研究。2017年至2019年对61个小麦田进行的调查收集了该地区63个菌株，通过16S rRNA基因分析鉴定为 spp.。先前报道的一种具有物种特异性引物的实时PCR方案能够鉴定出44个菌株为 ，它是小麦和其他谷类作物细菌性条斑病（BLS）的病原菌。对四个管家基因（ 、 、 和 ）进行多位点序列分析表明，这些菌株与 pv. 关系最为密切，pv. 是最常与小麦细菌性条斑病相关的致病型。应用多位点序列分型法来检测 菌株的遗传多样性。菌株被分为四种不同的序列类型，其中三种在全球范围内此前已有报道。此外，从患病小麦叶片中获得了17个不属于 的 菌株。系统发育分析表明，这些菌株与 密切相关，并与先前从明尼苏达州小麦中分离出的未鉴定的 菌株聚集在一起。在对一种易感细菌性条斑病的小麦品种进行的活体致病性测定中，pv. 菌株引发了细菌性条斑病典型的褐色坏死症状，而非 属菌株引发了一种非典型的干坏死症状。这些发现表明，当地小麦田受到pv. 的影响，并且受到 属内一种新的小麦病原菌的影响。
