拮抗细菌对香蕉枯萎病菌的离体抑菌活性研究

In vitro inhibition activity of antagonistic bacterium against Fusarium oxysporum f. sp. cubense

通过平板对峙培养，筛选出对香蕉枯萎病菌有拮抗作用的细菌6株：B05、B23、B44、B105、B133和B146，测定其抑菌带宽度达10～15mm。拮抗细菌的发酵液对病菌菌丝生长的抑制率为83．71％～88．76％，而经高温灭活的发酵液对病菌菌丝生长的抑制率为16．85％～33．48％；拮抗菌的非挥发性代谢产物对病菌菌丝生长的抑制率为74．72％～87．36％；挥发性代谢产物对病菌菌丝生长的抑制率为15．30％～37．64％。拮抗细菌发酵液在一定浓度范围内均能有效地抑制病菌孢子萌发，且浓度越高，抑制能力越强。拮抗菌株B05抑菌作用最稳定、抑菌活性最高，菌株B44抑制孢子萌发效果最好。

Six bacterial isolates （i. e. , B05, B23, B44, B105, B133 and B146） showed considerable antibiosis toward race 4 of Fusarium oxysporum f. sp. cubense, the Panama wilt pathogen of banana. Diameter of the inhibition zone ranged from 10 mm to 15 mm by pairing culture on PDA plate. The rate of pathogen mycelium growth inhibition of the bacterial isolates culture liquid ranged from 83.71% to 88.76% on PDA plate, as compared to 16. 85% to 33.48% of the liquid after autoclave at 15 psi （121℃） for 20 rain. The non--volatile and volatile active metabolites of the isolates showed inhibition rates on the pathogen＇s mycelium growth ranging from 74. 72% to 87.36 % and from 15.30 % to 37.64 %, respectively. The culture filtrates of all isolates were found to be effective in reducing spores germination of F. oxysporum. Among them, B05 showed the most stable and greatest inhibition activity, while B44 most effective in inhibiting the spore germination.