Fusaricidin Biosynthesis Is Controlled via a KinB-Spo0A-AbrB Signal Pathway in Paenibacillus polymyxa WLY78

Fusaricidins produced by are important lipopeptide antibiotics against fungi. The (fusaricidin biosynthesis) operon is responsible for synthesis of fusaricidins. However, the regulation mechanisms of fusaricidin biosynthesis remain to be fully clarified. In this study, we revealed that fusaricidin production is controlled by a complex regulatory network including KinB-Spo0A-AbrB. Evidence suggested that the regulator AbrB represses the transcription of the gene cluster by direct binding to the promoter, in which the sequences (5'-AATTTTAAAATAAATTTTGTGATTT-3') located from -136 to -112 bp relative to the transcription start site is required for this repression. Spo0A binds to the promoter that contains the Spo0A-binding sequences (5'-TGTCGAA-3', 0A box) and in turn prevents the further transcription of . The decreasing concentration of AbrB allows for the derepression of the promoter repressed by AbrB. The genome of . WLY78 contains two orthologs (named Kin1508 and Kin4833) of KinB, but only Kin4833 activates sporulation and fusaricidin production, indicating that this kinase may be involved in phosphorylating Spo0A to initiate sporulation and regulate the transcription. Our results reveal that Kin4833 (KinB), Spo0A, and AbrB are involved in regulation of fusaricidin production and a signaling mechanism that links fusaricidin production and sporulation.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.