Kurstakin triggers multicellular behaviors in Bacillus cereus AR156 and enhances disease control efficacy against rice sheath blight.

Kurstakins is the latest discovered family of lipopeptides secreted by . In this study, the effects of kurstakin on the direct antagonism, multicellularity and disease control ability of AR156 were explored. An insertion mutation in non-ribosomal peptide synthase responsible for kurstakin synthesis led to a significant reduction of antagonistic ability of AR156 against the plant pathogenic fungi , , and f. sp. . The loss of kurstakin synthesis ability significantly impaired the swarming motility of AR156 and reduced biofilm formation and amyloid protein accumulation. Although the loss of kurstakin synthesis ability did not reduce the competitiveness of AR156 under laboratory condition, the colonization and environmental adaptability of the mutant was significantly weaker than that of wild type AR156 on rice leaves. Cell surface of wild type AR156 colonized on the leaf surface was covered by thick biofilm matrix under scanning electron microscope, but not in the mutant. The colonization ability on rice roots and control efficacy against rice sheath blight disease of the mutant were also impaired. Thus, kurstakin participates in the control of plant diseases by AR156 through directly inhibiting the growth of pathogenic fungi, and improving long-term environmental adaptability and colonization of AR156 on the host surface by triggering multicellularity. This study explored the multiple functions of kurstakin in plant disease control by .