Key Laboratory of Agricultural Biodiversity and Pests Control, Yunnan Agricultural University, Kunming 650201, China.
J Microbiol Biotechnol. 2013 Mar;23(3):313-21. doi: 10.4014/jmb.1208.08065.
Bacillus subtilis XF-1, a strain with demonstrated ability to control clubroot disease caused by Plasmodiophora brassicae, was studied to elucidate its mechanism of antifungal activity against P. brassicae. Fengycin-type cyclopeptides (FTCPs), a well-known class of compounds with strong fungitoxic activity, were purified by acid precipitation, methanol extraction, and chromatographic separation. Eight homologs of fengycin, seven homologs of dehydroxyfengycin, and six unknown FTCPs were characterized with LC/ESI-MS, LC/ESI-MS/MS, and NMR. FTCPs (250 microg/ml) were used to treat the resting spores of P. brassicae (10(7)/ml) by detecting leakage of the cytoplasm components and cell destruction. After 12 h treatment, the absorbencies at 260 nm (A(260)) and at 280 nm (A(280)) increased gradually to approaching the maximum of absorbance, accompanying the collapse of P. brassicae resting spores, and nearly no complete cells were observed at 24 h treatment. The results suggested that the cells could be cleaved by the FTCPs of B. subtilis XF-1, and the diversity of FTCPs was mainly attributed to a mechanism of clubroot disease biocontrol.
枯草芽孢杆菌 XF-1 是一种具有控制由根肿菌引起的根肿病能力的菌株，研究其对根肿菌的抗真菌活性机制。通过酸沉淀、甲醇提取和色谱分离，从枯草芽孢杆菌 XF-1 中纯化出丰原素型环肽（FTCPs），这是一类具有强抑菌活性的化合物。采用 LC/ESI-MS、LC/ESI-MS/MS 和 NMR 对 8 种丰原素同系物、7 种去羟丰原素同系物和 6 种未知 FTCPs 进行了表征。用 FTCPs（250μg/ml）处理根肿菌休止孢子（10(7)/ml），通过检测细胞质成分泄漏和细胞破坏来检测其作用。12 h 处理后，260nm（A(260))和 280nm（A(280))的吸光度逐渐增加到接近最大吸光度，伴随着根肿菌休止孢子的崩溃，24 h 处理时几乎没有观察到完整的细胞。结果表明，枯草芽孢杆菌 XF-1 的 FTCPs 可以切割细胞，FTCPs 的多样性主要归因于根肿病生物防治的一种机制。
