Study on antifungal active substance of Bacillus subtilis F-2
枯草芽孢杆菌F-2抗植物病原真菌活性物质的研究

Effects of Bacillus subtilis F-1 and F-2 on inhibiting the growth of Fusarium oxysporum f.sp. cucumerinum (F.o.c) were studied by a co-culture experiment. The results showed that the growth of F.o.c could be strongly inhibited by the specific metabolites of Bacillus subtilis F-2, but not by Bacillus subtilis F-1. It was guessed by LC-MS determination that the possible molecular weights of the specific metabolites were 1477.0, 1489.1 and 1505.1. It was further found by MALDI-TOF MS that there were two groups of homologues with a difference of 14 Da in molecular weights in the extract of Bacillus subtilis F-2. In the first group, there were 5 kinds of homologues with the molecular weights of 1462.8, 1476.8, 1490.8, 1504.8 and 1518.9, respectively, which were identified as lipopeptide antibiotics Fengycin B(C_ 14-18 ) by the method of mass fingerprinting. In the second group, the molecular weights of 5 kinds of homologues were 1432.8, 1446.8, 1460.8, 1474.8 and 1488.9, respectively, which were estimated as the isomer of Fengycin A(C_ 14-18 ) as only 2 Da difference in molecular weights.