大豆根腐病生防菌KJB04-11的鉴定及其产生的脂肽类抗生素

从大豆根围筛选到1株对尖孢镰刀菌和立枯丝核菌都具有很好拮抗作用的菌株KJB04-11,经形态观察、生理生化特征和16SrDNA序列分析,属于枯草芽孢杆菌(Bacillussubtilis)。具有抗菌活性的KJB04-11发酵液无菌滤液对热和酸碱具有较强的稳定性。采用SephadexG-25柱层析、反相HPLC和冷冻干燥从KJB04-11发酵液中分离纯化了抗菌活性成分。由红外光谱、MALDI-TOF-MS、氨基酸组成及脂肽合成酶基因扩增结果推测该菌株产生的抗菌物质为C16、C17的mycosubtilin和C15的surfactin。田间试验表明,大豆种子经KJB04-11发酵液包衣处理对大豆根腐病防效为53.6%,大豆产量提高12.5%。

Identification of bio-control bacterial strain KJB04-11 against soybean root rot disease and the produced lipopeptide antibiotics by the strain

A bacterial strain KJB04-11 with antagonistic effect against Fusarium oxysporum and Rhizoctonia solani was isolated from soybean rhizosphere.The strain was identified as Bacillus subtilis,based on its morphological,cultural,physiological,and biochemical characteristics,and 16S rDNA sequence analysis.The fermented filtrate with antagonistic activity showed certain thermostability and certain acidic and alkaline stability in the range of pH 1.0-13.0.The antagonistic active compositions in the fermented filtrate were purified by gel filtration on Sephadex G-25 column and RF-HPLC,and preliminarily identified as C16 mycosubtilin,C17 mycosubtilin,and C15 surfactin by infrared spectra,MALDI-TOF mass spectrum,amino acid composition analysis,and amplification of lipopeptide synthase gene.In field trial,the control efficacy of seed coating agent prepared with KJB04-11 against soybean root rot disease was 53.6%,and the soybean yield was increased by 12.5%.