魔芋内生拮抗细菌的分离及其抗菌物质特性研究

Isolation of endophytic antagonistic bacterium from Amorphophallus konjac and research on its antibacterial metabolite

摘要:

从魔芋的内生菌中筛选到能抑制魔芋软腐病病原菌生长、产芽胞的杆状细菌,16SrDNA序列分析表明该菌是一株枯草芽胞杆菌,命名为BSn5。BSn5的胞外蛋白提取液有抗菌活性,并具有对热不稳定,对蛋白酶K敏感,对胰蛋白酶不敏感的特性,SDS-PAGE检测显示该蛋白提取液仅由分子量为31.6kDa的蛋白质组成。通过非变性聚丙烯酰胺凝胶电泳纯化该蛋白,纯化的蛋白能够抑制软腐病病原菌的生长,进一步表明该31.6kDa蛋白即为该菌的抗菌活性物质。该蛋白与目前所知的枯草芽胞杆菌产生的抗菌物质均不同,可能是一种新的抗菌蛋白。

Abstract:

An endophytic antagonistic bacterium was isolated from Amorphophallus konjac calli. In order to identify this bacterium, 16S rDNA was amplified and partially sequenced. Sequence comparison showed that this sequence has the highest similarity to that in Bacillus subtilis，with 99.0％ identities. That demonstrated this bacterium belongs to Bacillus subtili, named BSn5. The extracted extracellular protein from strain BSn5 had antibacterial activity against Erwinia carotovora subp. carotovora, which was unstable after heated, sensitive to proteinase K and resistant to trypsin. There was only a 31.6kDa protein component as by SDS-PAGE detection. Nondenaturing polyacrylaminde gel was used to purify this protein. The purified 31.6kDa protein exhibited inhibitory activity against Erwinia carotovora subp. carotovora. This protein is different from all known metabolites from Bacillus subtilis, suggesting that it may be a novel antibacterial protein.