Isolation and identification of lipopeptides produced by endophytic bacteria Bacillus subtilis E1R-j and its anti-fungal mechanism studies

The entophytic Bacillus subtilis E1R-j was isolated from wheat roots. The objective of this study was to isolate and identify the lipopeptides produced by B. subtilis strain E1R-j using acid precipitation, FPLC and MALDI-TOF/TOF-MS techniques. Four antifungal fractions, P1, P2, P3 and P4, were separated from the lipopeptides, and the P3 fraction has been shown to bear the major antifungal activity. According to the mass spectra analysis, P3 consisted of fengycins. The further experiments demonstrated that P3 was stable to high temperature, and even remained antifungal activity at 121 ℃ for 30 min. Microscope observation revealed that the P3 strongly inhibited the growth of mycelial. Furthermore, it can also cause deformities of mycelial cells, disintegration of the cell wall, the leakage of cytoplasm and so on.