Fullem Kiersten R, MacLellan Michelle P, Poudel Mousami, Goss Erica M, Potnis Neha, Minsavage Gerald V, Jones Jeffrey B, Paret Mathews L
Department of Plant Pathology, University of Florida, Gainesville, FL, USA.
Department of Plant Pathology, University of Georgia, Tifton, GA, USA.
Int J Syst Evol Microbiol. 2024 Dec;74(12). doi: 10.1099/ijsem.0.006596.
Three fluorescent bacterial strains, K1, K13 and K18, were obtained from watermelon () foliage symptomatic of bacterial leaf spot of cucurbits in Florida. The strains underwent phenotypic characterization, including LOPAT (levan production, oxidase activity, pectolytic activity on potato, arginine dihydrolase production and hypersensitive response (HR) on both tobacco and tomato) and pathogenicity testing on watermelon and squash seedlings. Whole-genome sequencing of the isolates was performed, and multi-locus sequence analysis (MLSA) utilizing housekeeping genes , , and placed the isolates into two distinct clades within the genus. Average nucleotide identity based on blast (ANIb) was used to compare the isolates to reference genomes. Using ANIb, the closest relatives to the novel strains were identified as (K1 : 82.58%; K13 : 83.77%) and (K18 : 87.16%), although ANIb values were below the 95% threshold for species delineation. DNA-DNA hybridization (genome-genome distance calculation method), comparison to the online Type Genome Server, Biolog biochemical profiling and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry were also unable to identify the isolates as any known species of . Based on the combination of genetic and phenotypic data, we conclude that these isolates represent two novel species, for which we propose the names sp. nov. (K1, K13, NCPPB 4759=LMG 33364) and sp. nov. (K18, NCPPB 4761=LMG 33365). The specific epithet was chosen for the geographic location of isolation (northern Florida), while designates the host of origin ().
从佛罗里达州有葫芦科细菌性叶斑病症状的西瓜叶片中获得了三株荧光细菌菌株，即K1、K13和K18。对这些菌株进行了表型特征分析，包括LOPAT（果聚糖产生、氧化酶活性、对马铃薯的果胶分解活性、精氨酸双水解酶产生以及对烟草和番茄的过敏反应（HR））以及对西瓜和南瓜幼苗的致病性测试。对分离株进行了全基因组测序，并利用管家基因、、和进行多位点序列分析（MLSA），将分离株归入属内两个不同的进化枝。基于blast的平均核苷酸同一性（ANIb）用于将分离株与参考基因组进行比较。使用ANIb，确定与新菌株亲缘关系最近的是（K1：82.58%；K13：83.77%）和（K18：87.16%），尽管ANIb值低于物种划分的95%阈值。DNA-DNA杂交（基因组-基因组距离计算方法）、与在线模式基因组服务器的比较、Biolog生化分析以及基质辅助激光解吸/电离飞行时间质谱也无法将分离株鉴定为任何已知的物种。基于遗传和表型数据的综合分析，我们得出结论，这些分离株代表两个新的物种，我们将其命名为新种（K1、K13、NCPPB 4759 = LMG 33364）和新种（K18、NCPPB 4761 = LMG 33365）。特定的种加词是根据分离地点（佛罗里达州北部）选择的，而则指定了原始宿主（西瓜）。
