生防菌BMP-11对瓜果腐霉病菌的抑制活性及其鉴定

Antifungal activity of antagonistic strain BMP-11 against Pythium aphanidermatum and its identification

为明确生防细菌BMP-11对黄瓜猝倒病的控制作用及其分类地位,采用平板对峙法结合显微观察确定其对致病菌瓜果腐霉的抑制活性,进行BMP-11发酵液对黄瓜猝倒病的防病促生试验,并采用形态及培养特征观察、生理生化测定结合16S rDNA序列分析对其进行鉴定。结果表明,BMP-11对瓜果腐霉病菌具有较强的抑制活性,并可使菌丝体细胞壁裂解,原生质聚集、外溢,进而抑制卵孢子形成;发酵液土壤处理对种子发芽率无显著影响,并可提高黄瓜出苗率,促进黄瓜植株生长;盆栽防病试验结果显示,BMP-11对由瓜果腐霉病菌引起的黄瓜猝倒病的防治效果为62.2%,与对照药剂霜霉威无显著差异。根据16S rDNA序列分析的系统发育树,BMP-11与多粘类芽孢杆菌Paenibacillus polymyxa GBR-1基因序列的同源性最高,结合形态及培养特征观察和生理生化鉴定结果,初步确定该菌株为多粘类芽孢杆菌。

In order to evaluate control efficacy to damping-off on cucumber of antagonistic bacterium strain BMP-11, the inhibition effect to the pathogen of Pythium aphanidermatum were tested using dual culture method and optical microscope observation, plant growth promotion and biocontrol tests were also carried with ferment broth of BMP-11; and to determine its classification status, identification experiments were proceed by morphology and culture feature observation, and physiological and biochemical characteristics determination and 16S rDNA sequences assay. The results showed that strain BMP-11 had strong inhibitory action against Pythium aphanidermatum. It could make the cell wall of the mycelium broken, the protoplasm condensed and leaked, and inhibit the hypha form oocyte. In addition, there had no inhibition on the germination rate of cucumber seed, and it could also increase the emergence rate and improve the growth of cucumber seedlings. The disease control effect of BMP-11 on cucumber damping- off was 62.2% in plot test in greenhouse, which was similar to that of the commercial fungicide propamocarb. BMP-11 had the nearest evolutionary distance with Paenibacillus polymyxa GBR-1 by phylogenetic tree of 16S rDNA sequences, combining with its results of morphological, culture and biochemical property analysis, it was identified as Paenibacillus polymyxa.