巨大芽胞杆菌YB-3的筛选、鉴定及其对生姜青枯病的生防效果研究

青枯病（bacterial wilt）是生姜上的一种细菌土传毁灭性病害，化学防治易污染环境且常规化学药剂很难在土壤中起到持续控病的作用，生物防治是其理想的防治方法。为开发对生姜青枯病有效的生防措施，对从生姜根际土壤中分离的一株生防细菌YB-3进行了鉴定，并对其生物学特性及生防效果进行了研究，以丰富生防菌株资源库。采用抑菌圈法筛选拮抗细菌，对效果最好的拮抗菌株做盆栽试验，测定其对生姜青枯病的防治效果，根据形态特征、生理生化特性以及16S rDNA序列对筛选得到的优良菌株进行鉴定。试验结果表明，该拮抗菌在平皿上对青枯菌的抑菌率为50.67%，盆栽试验对青枯病的防治效果为60.86%；经16S rDNA序列分析，并结合形态学和生理生化特征，将菌株YB-3鉴定为巨大芽胞杆菌Bacillus megaterium。YB-3是一株具有开发利用价值的姜青枯病生防菌株。

Screening,Identification and Control Efficacy of Bacillus megaterium with Antagonist Activity against Ginger Wilt

Bacterial wilt of ginger, referred to as “ginger blast” caused by Ralstonia solanacearum, is the destructive pathogen of ginger reported from all the ginger growing countries. But there is no means available for effective control of the disease in field. Obtaining effective strains with disease control activity is an urgent prerequisite for biological control efficiency. This study was performed to explore if the plant growth-promoting rhizobacteria (PGPR) in ginger plants had any potential to induce resistance to Ralstonia solanacearum. Three strains were selected for evaluation of ginger growth promotion ability and control efficacy against the ginger wilt through culture dish and pot culture method, and the dominant strain YB-3 was identified based on its 16S rDNA sequence homology with the related bacteria from GenBank as well as physiological and biochemical characters. The results showed that the control effect of strain YB-3was 60.86% in pot experiment. The strain YB-3 was identified as Bacillus megaterium by morphological observations, physiological and biochemical tests, combined with 16S rDNA analysis. These results indicated that the strain YB-3 had the exploitation value against ginger wilt disease.