Isolation, identification and characterization of biopotential cyclic lipopeptides from Bacillus subtilis strain JN005 and its antifungal activity against rice pathogen Magnaporthe oryzae

In the present study, the cyclic lipopeptides extracted from Bacillus subtilis strain JN005 showed inhibition activity against the rice phytopathogenic fungus Magnaporthe oryzae. The isolated cyclic lipopeptides tolerated high temperature, extreme acidity, extreme alkalinity and ultraviolet radiation. The growth of the mycelium and conidia of the rice phytopathogenic fungus M. oryzae was abnormal after cyclic lipopeptide treatment. In vitro inoculation revealed that cyclic lipopeptide treatment reduced disease incidence by 17.78 ± 2.72% and 22.22 ± 3.51% in the curative and preventive groups, respectively, controlling rice leaf blast. Whole genome sequencing showed that B. subtilis strain JN005 had a circular chromosome with a length of 4,167,853 bp, an average G + C content of 43.86% and 4294 coding DNA sequences. Six gene clusters were identified based on genome analysis encoding for secondary metabolite synthesis of surfactin, fengycin, bacillibactin, bacillaene, subtilosin and bacilysin. Ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry and ultra performance liquid chromatography-quadrupole-time of flight-mass/mass spectrometry analyses of cyclic lipopeptides further demonstrated the production of surfactin and fengycin derivatives by B. subtilis strain JN005. This study provides insight into the biocontrol potential of B. subtilis strain JN005 and will facilitate its application for the management of rice blast disease caused by M. oryzae.