香蕉枯萎病拮抗细菌的筛选、鉴定及其抑菌性研究

Screening and Identification of Antagonistic Bacteria against Banana Fusarium wilt and Its Inhibitory Characteristics

本文从原始森林土壤中分离纯化得到733株细菌菌株,采用平板对峙法筛选出3株对香蕉枯萎病具有高效拮抗作用的细菌,并进行形态特征观察、生理生化特性测定及16S rDNA序列分析。结果表明,S1,S23鉴定为枯草芽孢杆菌(Bacillus subtilis),S3鉴定为地衣芽孢杆菌(Bacillus licheniformis)。不同浓度拮抗菌的发酵滤液均可抑制病原菌孢子萌发和生长,随着发酵滤液浓度的增加,抑制效果增强。当3种拮抗菌发酵滤液浓度达到70%时,其在高度抑制水平上的抑制率分别为46%、57%和50%。抑菌圈附近病原菌菌丝末端膨大成球状,菌丝破裂、消解、菌丝体分枝增多。

733 bacterial strains were isolated and purified from the soil samples collected from primeval forest,in which three antagonistic bacterial strains screened out with slab confrontation method had fairly strong inhibition of banana Fusarium wilt,and their morphology,physiological,biochemical characteritics and 16S rDNA sequence were analyzed.The result showed that the denominated strain S1,S23 were Bacillus subtilis,and strain S3 was Bacillus licheniformis.Different concentrations of antagonistic bacteria fermentation filtrate could inhibit spore germination and growth of pathogens effectively,and with the increase of fermentation filtrate concentration,the inhibition effect increased.When the fermentation filtrate concentration of three antagonistic bacteria reached 70 ％,the inhibiting rates at high inhibition level were 46 ％,57 ％,50 ％,respectively.In addition,mycelial growth of the pathogen near the bacteriostatic circle was also inhibited significantly as indicated by swelled hyphal tip,which increased hyphal branches,broken,constricted and dissolved mycelia.