连作花生田根际土壤优势细菌的分离和鉴定

Isolation and Identification of Dominant Bacteria in Rhizosphere of Continuous Peanut Cropping

采用土壤稀释分离法,从不同连作年限花生根际土壤中分离优势细菌,结合菌株形态特征、培养性状、生理生化特征及16S rDNA序列分析结果,对优势细菌进行鉴定。结果表明,种植过花生及花生连作后,土壤中优势细菌种类发生明显变化,从连作花生田根际土壤中分离鉴定出7种优势细菌,分别为Leifsonia xyli、氯酚节杆菌(Arthrobacter chlorophenolicus)、黄色微杆菌(Mi-crobacterium flavescens)、鞘氨醇单胞菌属细菌(Sphingomonassp.)、巴斯德菌属细菌(Pasteurel-lasp.)、简单芽孢杆菌(Bacillus simplex)和巨大芽孢杆菌(Bacillus megaterium)。未发现花生病原细菌,说明花生连作障碍的主要因素不是细菌引发花生病害所导致,但花生种植后土壤中优势细菌种类会发生明显变化。细菌与花生连作障碍之间的关系还需进一步研究。

The dilution-plate method was used to isolate dominant bacteria from the rhizosphere soil of continuous peanut cropping.Through morphological specificity,culture shape,physiological-biochemical characteristics and sequence analysis of 16S rDNA,the bacterium strains were identified.The result showed that the type of dominant bacteria in rhizosphere soil changed significantly after the soil was planted with peanut and continuously planted with peanut.Severn types of bacteria were isolated and identified,which were Leifsonia xyli,Arthrobacter chlorophenolicus,Microbacterium flavescens,Sphingomonas sp.,Pasteurella sp.,Bacillus simplex and Bacillus megaterium.It was the first time to isolate and identify dominant bacteria systemically from the rhizosphere soil of continuous peanut cropping.All of the strains isolated were not pathogenic to peanut.It indicated that the primary factor of continuous peanut cropping barrier was not induced by bacteria causing peanut disease.But the type of dominant bacteria changed obviously after the soil was planted with peanut.The relationship of bacteria and continuous peanut cropping barrier needed further studied.