菌株BM-24的分离鉴定及对香蕉枯萎病菌的抑菌活性

为了从饼肥发酵液中分离筛选出对香蕉枯萎病菌Fusarium oxysporum f.sp.cubense有良好拮抗效果的菌株,以香蕉枯萎病病原菌为指示菌进行拮抗菌分离筛选.筛选得到29株拮抗菌,其中分离自菜子饼的菌株BM-24拮抗效果最显著.利用平板对峙法测定菌株BM-24抑菌谱,根据形态特征、培养特征及生理生化特征和16S rDNA序列分析对其进行鉴定,并测定其发酵液不同处理的抑菌活性.经鉴定,此菌株为甲基营养型芽胞杆菌Bacillus methylotrophicus,该菌株对供试的12种植物病原真菌均有很强的抑制作用,尤其对香蕉枯萎病菌1号和4号小种菌丝生长抑制作用最强,抑菌率分别达到87.2％和80.4％,其发酵液对香蕉枯萎病菌具有很强抑菌效果,抑菌活性主要源于菌体竞争.

Isolation, identification of BM-24 strains and its antifungal activity of antagonistic bacteria against Fusarium oxysporum f.sp.cubense

In order to isolate and screen antagonistic strains against Fusarium oxysporum f.sp.cubense of banana from fermentation cake fertilizer liquid, F.oxysporum was taken as indicative bacteria to separate and screen antagonistic bacteria. The results showed that 29 strains were isolated, among of which the strain BM-24 isolated from rapeseed cake had the highest antagonistic effect. The inhibition spectrum of the strain BM-24 was tested by plate stand-opposite culture method and identified using 16S rDNA sequence analysis combined with morphological characteristics, culture characteristics and physiological and biochemical characteristics. The antibacterial activity of different treatments on strain BM-24 fermentation liquid was tested furthermore. The strain was identified to be Bacillus methylotrophicus. It showed strong inhibition to 12 kinds of plant pathogenic fungi, especially to F.oxysporum Race 1 and Race 4 of banana with inhibition rates of 87.2% and 80.4% respectively. The strain BM-24 fermentation liquid had strong antagonist effects to F.oxysporum mainly because of the bacteria competition.