香蕉枯萎病生防细菌的筛选、鉴定及其抑菌作用

采用平板对峙法,从香蕉根部土样中分离到1株枯萎病拮抗芽孢杆菌XY-10。根据形态特征及16S rDNA分析将其鉴定为多粘类芽孢杆菌Paenibacillus polymyxa。拮抗试验表明菌株XY-10不同浓度的发酵滤液均可抑制病原菌孢子萌发和生长,当发酵滤液浓度分别为10%、30%和50%时,其在高度抑制水平上的抑制率分别为7%、23%和40%。经发酵滤液处理,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。

Isolation, Identification and Antagonistic Acitivity of Biocontrol Bacterium against Fusarium oxysporum f. sp. cubense

In this study,an antagonistic bacterial strain XY-10 against Fusarium oxysporum f.sp.cubense was isolated from banana rhizosphere soil by dual culture,and identified as Paenibacillus polymyxa according to its morphology and homology analysis of the 16S rDNA sequence（GenBank accession GQ199631）.Its fermentation filtrate could inhibit spore germination of the pathogen effectively.When concentration of the fermentation filtrate were 10%,30%,50%,the inhibiting rates at high inhibition level were 7%,23%,40%,respectively.In addition,mycelial growth of the pathogen was also inhibited significantly as indicated by swelled hyphal tip,increased hyphal branches,shortened branch intervals,and broken,constricted and/or dissolved mycelia.