†Tsukuba Research and Technology Center, SDS Biotech K.K., Midorigahara, Tsukuba, Ibaraki 300-2646, Japan.
‡Department of Agricultural Chemistry, Faculty of Agriculture, Tottori University, Koyama, Tottori 680-8553, Japan.
J Agric Food Chem. 2015 Jun 10;63(22):5344-53. doi: 10.1021/acs.jafc.5b01198. Epub 2015 May 27.
We previously reported that Bacillus amyloliquefaciens biocontrol strain SD-32 produces powerful antifungal lipopeptides, C17 bacillomycin D homologues. In the course of the investigation we found that the antifungal activity of the culture supernatant of this bacterium was not ascribed exclusively to bacillomycin D. We attempted to identify metabolites other than bacillomycin D to gain insight into the mechanism for the biocontrol by this bacterium. After purifying the fractions of the culture supernatant exhibiting synergistic activity with bacillomycin D, we isolated two new cyclic lipodepsipeptides, anteiso-C13 and iso-C13 [Ile(7)]surfactins, together with three known [Ile(7)]surfactins. Interestingly, [Ile(7)]surfactins showed synergistic activities with bacillomycin D to gray mold disease on cucumber leaves but not to Botrytis cinerea itself in vitro, suggesting that the synergistic effects might be on infection processes of the fungus. Actually, we observed that they did not show synergistic actions on conidial germination or mycelial growth of B. cinerea on the leaves.
我们之前曾报道过解淀粉芽孢杆菌生防菌株 SD-32 能够产生具有强大抗真菌活性的脂肽类化合物，即 C17 杆菌霉素 D 类似物。在研究过程中，我们发现该细菌培养上清液的抗真菌活性并非完全归因于杆菌霉素 D。我们试图鉴定除杆菌霉素 D 以外的代谢产物，以深入了解该细菌的生防机制。在对表现出与杆菌霉素 D 协同活性的培养上清液的各个馏分进行纯化后，我们分离出两种新的环状脂肽类化合物，即 anteiso-C13 和 iso-C13 [Ile(7)]表面活性剂，以及三种已知的 [Ile(7)]表面活性剂。有趣的是，[Ile(7)]表面活性剂与杆菌霉素 D 对黄瓜叶片上的灰霉病表现出协同作用，但在体外对灰葡萄孢本身没有协同作用，这表明协同作用可能发生在真菌的侵染过程中。实际上，我们观察到它们在叶片上对灰葡萄孢的分生孢子萌发或菌丝生长没有协同作用。
