为从烟草根际土壤中筛选得到对烟草土传病原真菌具有拮抗作用的细菌菌株，用稀释平板法分离土壤样品获得根际细菌菌株，再用平板对峙培养法测定细菌菌株的拮抗作用，通过形态特征观察、生理生化测定及16S rDNA序列分析来鉴定拮抗细菌的种类。结果表明，从30份根际土壤样品中共分离、纯化得到180个细菌单菌落，其中49株细菌对供试病原真菌具有一定的抑制作用。菌株TS681、TS682和TS683对3种病原真菌均具有较好的拮抗作用，对瓜果腐霉的抑菌率均大于51.43%，对寄生疫霉的抑菌率均大于68.75%，对尖孢镰刀菌的抑菌率均大于60.00%。结合菌株的形态特征、生理生化特征与16S rDNA序列的分析结果，将菌株TS681、TS682和TS683鉴定为多粘类芽孢杆菌（Paenibacillus polymyxa）。%To isolate bacteria strains which possess antagonistic activities against soil-borne pathogenic fungi of tobacco from tobacco rhizosphere soil,dilution plating method and dual culture method were adopted to isolate and screen antagonistic bacteria. The bacteria morphological features were observed, and in addition physiological and biochemical experiments and 16S rDNA sequence analysis were used to identify antagonistic strains. A total of 180 bacterial isolates were obtained from 30 rhizosphere soil samples by separation and purification,in which 49 strains had antagonistic function against soil-borne pathogenic fungi. Strain TS681, TS682 and TS683 were strongly antagonistic towards three kinds of pathogenic fungi,and its antagonistic rate to Pythium aphanidermatum,Phytophthora parasitica and Furasium oxysporum reached above 51.43%,68.75%and 60.00%,respectively. Combined with morphological characteristics, physiological and biochemical characteristics and 16S rDNA sequence analysis, the above three strains were identified as Paenibacillus polymyxa.
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