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目的筛选并鉴定软腐白菜根系土壤中分离出的细菌。方法从河南省大白菜田成熟白菜病株根系土壤采集样品,利用模拟原环境的培养基成分和条件,对样品中的细菌进行分离和培养。对菌株进行形态学观察、生理生化特征鉴定以及16S r RNA基因序列测定、比对分析和系统发育树构建,对菌株进行初步分类鉴定。结果分离到的一株编号为Q2S2-18A2的菌株16Sr DNA与代夫特菌属内的Delftia lacustris 332 T(EU888303)具有最高的相似性,相似值为98.60%。结论模拟原环境培养基,结合经典分类学方法和16S r RNA基因序列比对分析、构建系统发育树,可分离并鉴定软腐白菜根系土壤中的机会致病菌湖生代夫特菌。
Objective To screen and identify the bacteria isolated from the soft soil of Brassica campestris. Methods Samples were taken from the root soil of the mature cabbage plants in the Chinese cabbage field in Henan Province. The bacteria in the samples were isolated and cultured by using the original culture medium composition and conditions. The strains were observed morphologically, biochemical and physiological characteristics of 16S rRNA gene sequence analysis, alignment analysis and phylogenetic tree construction, preliminary identification of strains. Results The strain 16Sr DNA isolated from a strain Q2S2-18A2 had the highest similarity with Delftia lacustris 332 T (EU888303) in Deltacterium, with a similarity of 98.60%. CONCLUSIONS: The phylogenetic tree was constructed based on classical taxonomic method and 16S rRNA gene sequence alignment, which could be used to isolate and identify the opportunistic pathogenic bacterium H.fetians in soft-rotted cabbage root soil.