Langlois Paul A, Snelling Jacob, Hamilton John P, Bragard Claude, Koebnik Ralf, Verdier Valérie, Triplett Lindsay R, Blom Jochen, Tisserat Ned A, Leach Jan E
First, second, sixth, seventh, ninth, and tenth authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins 80523-1177; second author: Department of Horticulture, Oregon State University, Corvallis 97331; third author: Department of Plant Biology, Michigan State University, East Lansing 48824; fourth author: Université catholique de Louvain, Earth and Life Institute, B1348 Louvain-la-Neuve, Belgium; fifth and sixth authors: IRD, CIRAD, University Montpellier, Interactions Plantes Microorganismes Environnement (IPME), 34394 Montpellier, France; seventh author: Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven; and eighth author: Bioinformatics & Systems Biology, Justus-Liebig-University Giessen, 35392 Giessen, Hesse, Germany.
Phytopathology. 2017 May;107(5):519-527. doi: 10.1094/PHYTO-08-16-0286-R. Epub 2017 Mar 28.
Prevalence of Xanthomonas translucens, which causes cereal leaf streak (CLS) in cereal crops and bacterial wilt in forage and turfgrass species, has increased in many regions in recent years. Because the pathogen is seedborne in economically important cereals, it is a concern for international and interstate germplasm exchange and, thus, reliable and robust protocols for its detection in seed are needed. However, historical confusion surrounding the taxonomy within the species has complicated the development of accurate and reliable diagnostic tools for X. translucens. Therefore, we sequenced genomes of 15 X. translucens strains representing six different pathovars and compared them with additional publicly available X. translucens genome sequences to obtain a genome-based phylogeny for robust classification of this species. Our results reveal three main clusters: one consisting of pv. cerealis, one consisting of pvs. undulosa and translucens, and a third consisting of pvs. arrhenatheri, graminis, phlei, and poae. Based on genomic differences, diagnostic loop-mediated isothermal amplification (LAMP) primers were developed that clearly distinguish strains that cause disease on cereals, such as pvs. undulosa, translucens, hordei, and secalis, from strains that cause disease on noncereal hosts, such as pvs. arrhenatheri, cerealis, graminis, phlei, and poae. Additional LAMP assays were developed that selectively amplify strains belonging to pvs. cerealis and poae, distinguishing them from other pathovars. These primers will be instrumental in diagnostics when implementing quarantine regulations to limit further geographic spread of X. translucens pathovars.
引起谷类作物叶条斑病（CLS）以及饲料和草坪草细菌性枯萎病的燕麦黄单胞菌，近年来在许多地区的发生率有所上升。由于该病原菌在经济上重要的谷类作物中通过种子传播，这对国际和州际种质交换构成了威胁，因此需要可靠且强大的种子检测方案。然而，该物种分类学上的历史混乱使得开发准确可靠的燕麦黄单胞菌诊断工具变得复杂。因此，我们对代表六个不同致病型的15株燕麦黄单胞菌菌株进行了基因组测序，并将它们与其他公开可用的燕麦黄单胞菌基因组序列进行比较，以获得基于基因组的系统发育树，用于该物种的稳健分类。我们的结果揭示了三个主要聚类：一个由禾谷类致病型组成，一个由波动致病型和透明致病型组成，第三个由燕麦草致病型、禾本科致病型、早熟禾致病型和黑麦草致病型组成。基于基因组差异，开发了诊断性环介导等温扩增（LAMP）引物，可清晰区分引起谷类作物病害的菌株，如波动致病型、透明致病型、大麦致病型和黑麦致病型，与引起非谷类寄主病害的菌株，如燕麦草致病型、禾谷类致病型、禾本科致病型、早熟禾致病型和黑麦草致病型。还开发了其他LAMP检测方法，可选择性扩增属于禾谷类致病型和黑麦草致病型的菌株，将它们与其他致病型区分开来。在实施检疫规定以限制燕麦黄单胞菌致病型进一步地理扩散时，这些引物将有助于诊断。
