Hammami I, Rhouma A, Jaouadi B, Rebai A, Nesme X
Biostatistique et Signalization, Centre de Biotechnologie de Sfax, Tunisia.
Lett Appl Microbiol. 2009 Feb;48(2):253-60. doi: 10.1111/j.1472-765X.2008.02524.x.
The identification of a new compound active against Agrobacterium tumefaciens.
The culture conditions of a newly isolated Bacillus subtilis strain, designed 14B, were optimized, as a first step, to produce its bacteriocin (termed Bac 14B) for the biocontrol of Agrobacterium spp., the causal agents of the crown gall disease. Bac 14B was then partially purified and biochemically characterized. Bacillus subtilis 14B was observed to produce an antibacterial compound having a protinaceous nature. As estimated by sodium dodecyl sulfate-polyacrilamide gel electrophoresis (SDS-PAGE), the semi-purified bacteriocin substance was found to be a monomeric protein with a molecular weight of 21 kDa. While the latter's antimicrobial activity was completely stable during exposure to a temperature range of up to 100 degrees C for 2 h, its initial activity was totally lost at 121 degrees C for 20 min. The maximum bacteriocin production (4096 AU ml(-1)) was recorded after 96 h-incubation in an optimized Luria Bertani medium supplemented with 10 g l(-1) glucose, 15 g l(-1) K(2)HPO(4) and 5 g l(-1) MgSO(4) 7H(2)O at 30 degrees C in a shaking flask culture. Interestingly, the B. subtilis 14B culture supernatant that contained the bacteriocin under study was proved efficient in reducing both the percentage of galled plants and the number of galls in tomato.
The findings revealed that B. subtilis 14B and its bacteriocin are efficient in reducing the percentage of infections in plants caused by Ag. tumefaciens.
The results could be useful for the nurserymen who are particularly interested in the biocontrol of the crown gall disease.
鉴定一种对根癌土壤杆菌有活性的新化合物。
作为第一步，对新分离的枯草芽孢杆菌菌株14B的培养条件进行优化，以生产其细菌素（称为Bac 14B）用于生物防治根癌土壤杆菌，即冠瘿病的致病因子。然后对Bac 14B进行部分纯化并进行生化特性分析。观察到枯草芽孢杆菌14B产生一种具有蛋白质性质的抗菌化合物。通过十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳（SDS - PAGE）估计，半纯化的细菌素物质是一种分子量为21 kDa的单体蛋白。虽然该化合物在高达100℃的温度范围内暴露2小时，其抗菌活性完全稳定，但在121℃下20分钟其初始活性完全丧失。在优化后的Luria Bertani培养基中添加10 g l(-1)葡萄糖、15 g l(-1) K(2)HPO(4)和5 g l(-1) MgSO(4)·7H(2)O，于30℃摇瓶培养96小时后记录到最大细菌素产量（4096 AU ml(-1)）。有趣的是，含有该研究细菌素的枯草芽孢杆菌14B培养上清液被证明能有效降低番茄中患冠瘿病植株的百分比和瘿瘤数量。
研究结果表明枯草芽孢杆菌14B及其细菌素能有效降低根癌土壤杆菌引起的植物感染百分比。
该结果对特别关注冠瘿病生物防治的苗圃工作者可能有用。
