人参病原菌拮抗细菌的分离筛选与鉴定

为明确土壤拮抗细菌对人参常见病原菌的生防价值,从吉林省抚松县人参根际土壤中分离、纯化获得113株细菌,采用平板对峙法测定菌株的拮抗能力,通过温室盆栽试验研究其在土壤及人参根部的定殖规律,并通过形态、培养特征及16S r DNA序列分析进行分类鉴定。对峙试验结果表明,2株细菌对供试人参病原菌具有良好的拮抗广谱性,且多次验证其抑菌效果稳定。定殖研究结果表明,活性菌株SZ-56与SZ-60的定殖能力均达到显著水平,在土壤中的最大定殖菌量分别为每克土7.51×106CFU和7.28×106CFU,30 d后定殖菌量仍保持在105CFU;21 d后在人参根部的定殖菌量仍保持在每克根105CFU水平。根据形态、培养特征、生理生化指标和16S r DNA序列分析,确定SZ-56为内生芽胞杆菌Bacillus endophyticus,SZ-60为解淀粉芽胞杆菌B.amyloliquefaciens。

Screening and identification of antagonistic bacteria against Panax ginseng pathogeny fungus

In order to determine the biocontrol value of soil antagonistic bacteria against the common pathogenic bacteria of ginseng, 113 strains of bacteria were extracted and purified from ginseng rhizosphere soils in Fusong County of Jilin Province. The antagonistic ability of the bacterial strains was determined using flat plate confrontation method, and their colonization in soils and ginseng roots was studied through greenhouse pot experiment. Their classification statuses were analyzed by morphology, cultural characteristics and 16S rDNA sequences. The results showed that two strains had a good and broad spectrum of antagonistic activity towards selected pathogenic bacteria of ginseng, and the multiple tests confirmed that the antimicrobial effects were relatively stable. Colonization results showed that the colonization abilities of the active strains SZ-56 and SZ-60 reached significant levels, and the maximum colonization amount of SZ-56 and SZ-60 in the soils were 7.51×10⁶ CFU/g soil and 7.28×10⁶ CFU/g soil, respectively. The colonization amount of bacteria in ginseng roots remained at a level of 10⁵ CFU/g root 30 days later. Based on morphology, cultural characteristics, physiological and biochemical indexes and 16S rDNA sequence analysis, SZ-56 was determined as Bacillus endophyticus, and SZ-60 as B.amyloliquefaciens.