枸杞根腐病病原菌鉴定及其拮抗菌的筛选

Identification of the pathogen causing root rot of Lycium barbarum and screening of antagonists

为了针对根腐病实施有效的生物防治,分离鉴定枸杞根腐病病原菌及其拮抗菌,采用组织分离法获得腐根上的病原菌,结合形态学与分子生物学特征鉴定病原菌;利用稀释涂布、滤纸片法和共培养法从健康根际土壤筛选拮抗细菌,通过形态学观察、生理生化鉴定和16S rDNA序列分析对拮抗效果较好的菌株进行鉴定。结果表明:从枸杞根腐病分离得到腐皮镰刀菌(Fusarium solani)和尖孢镰刀菌(Fusarium oxysporum)两种主要致病菌,从健康枸杞根际土壤中分离获得12株对两种镰刀菌具有拮抗作用的细菌,其中J7-3、J7-8、J7-9和J10-8对腐皮镰刀菌的抑菌率均在80%以上,J7-3和J10-8对尖孢镰刀菌的抑菌率均在70%以上。菌株J7-3和J10-8对根腐病病原菌的抑菌作用较好,分别鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)和枯草芽孢杆菌(Bacillus subtilis),其中J10-8的拮抗作用和溶菌效果最好,可作为研发微生物菌剂的菌种资源。

To implement effective biological control against root rot disease,the pathogenic bacteria and their antagonistic bacteria were isolated and identified.The pathogens on decaying roots were isolated by tissue isolation method,and the types of fungi were identified by morphological and molecular biological characteristics.Antagonistic bacteria were screened from healthy rhizosphere soil by dilution coating method,filter paper method,and co-culture method.The strains with good antagonistic effect were identified by morphological observation,physiological and biochemical identification,and 16S rDNA sequence analysis.The results showed that Fusarium solani and Fusarium oxysporum were isolated from the root rot of Lycium barbarum.Twelve strains were isolated from the rhizosphere soil of healthy Lycium barbarum with antagonistic effects against two Fusarium strains.The inhibitory rates of J7-3,J7-8,J7-9 and J10-8 against F.solani were all above 80%,and the inhibitory rates of J7-3 and J10-8 against F.oxysporum were all above 70%.Strains J7-3 and J10-8,identified as Bacillus amyloliquefaciens and Bacillus subtilis,were well against root rot pathogens.Among them,J10-8 had the best antagonistic effect and bacteriolytic effect and can be used as a material resource for the development of microbial agents.