Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, Fujian, People's Republic of China.
Fujian Key Laboratory of Marine Genetic Resources, Xiamen, 361005, China.
Appl Microbiol Biotechnol. 2019 Jul;103(13):5367-5377. doi: 10.1007/s00253-019-09792-1. Epub 2019 May 3.
The bacterium, Bacillus amyloliquefaciens Pc3, was previously isolated from Antarctic seawater and has been found to show antagonistic activity against the fungus, Rhizoctonia solani ACCC 36316, which causes a severe disease known as Sclerotinia sclerotiorum in rapeseed plants. Bacillus lipopeptides had been widely used as biocontrol agents for plant diseases. In this study, we isolated 11 lipopeptide compounds from B. amyloliquefaciens Pc3 culture broth via reversed-phase high-performance liquid chromatography (RP-HPLC) and used matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) to identify these as iturin A (C, C, C, C), fengycin B (C, C, C, C), and surfactin (C, C, C). We further found that the addition of exogenous alkanoic acids, including myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, octadecanoic acid, and nonadecanoic acid, to the bacterial growth media could promote lipopeptide production and enhance the antifungal activities of crude lipopeptide extracts from B. amyloliquefaciens Pc3. In addition, the transcriptional levels of three lipopeptide synthesis genes, ituD, fenA, and srfA-A, and two fatty acid metabolism-related genes, FabI, which encodes enoyl-ACP reductase, and FadB, which encodes enoyl-CoA hydratase, were found to be upregulated in cells grown with exogenous alkanoic acids. Among the six alkanoic acids tested, those with odd carbon chain lengths had a greater effect on lipopeptide production, antifungal activity, and target gene upregulation than those with even carbon chain lengths. These results provide a practical approach for the efficient production of lipopeptides in Bacillus amyloliquefaciens Pc3.
先前从南极海水中分离到的细菌，解淀粉芽孢杆菌 Pc3，对真菌立枯丝核菌 ACCC 36316 具有拮抗活性，该真菌可导致油菜植物的严重病害，即菌核病。芽孢杆菌脂肽已被广泛用作植物病害的生物防治剂。在这项研究中，我们通过反相高效液相色谱（RP-HPLC）从解淀粉芽孢杆菌 Pc3 发酵液中分离出 11 种脂肽化合物，并使用基质辅助激光解吸电离飞行时间质谱（MALDI-TOF-MS）鉴定这些化合物为丰原素 A（C14、C15、C16、C17）、芬荠素 B（C14、C15、C16、C17）和表面活性素（C13、C14、C15）。我们进一步发现，向细菌生长培养基中添加外源性烷酸，包括月桂酸、十五烷酸、棕榈酸、十七烷酸、硬脂酸和十九烷酸，可以促进脂肽的产生，并增强解淀粉芽孢杆菌 Pc3 粗脂肽提取物的抗真菌活性。此外，三个脂肽合成基因 ituD、fenA 和 srfA-A 以及两个与脂肪酸代谢相关的基因 FabI 和 FadB 的转录水平被发现在外源烷酸存在下上调，FabI 编码烯酰-ACP 还原酶，FadB 编码烯酰-CoA 水合酶。在所测试的六种烷酸中，具有奇数碳链长度的烷酸对脂肽产生、抗真菌活性和靶基因上调的影响大于具有偶数碳链长度的烷酸。这些结果为解淀粉芽孢杆菌 Pc3 中脂肽的高效生产提供了一种实用方法。
