AUTHOR=Zhao Dongying , Li Hui , Cui Yanru , Tang Shengyue , Wang Chengqiang , Du Binghai , Ding Yanqin 

TITLE=MsmR1, a global transcription factor, regulates polymyxin synthesis and carbohydrate metabolism in Paenibacillus polymyxa SC2

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1039806

DOI=10.3389/fmicb.2022.1039806

ISSN=1664-302X

ABSTRACT=<p>The multiple-sugar metabolism regulator (MsmR), a transcription factor belonging to the AraC/XylS family, participates in polysaccharide metabolism and virulence. However, the transcriptional regulatory mechanisms of MsmR1 in <italic>Paenibacillus polymyxa</italic> remain unclear. In this study, knocking out <italic>msmR1</italic> was found to reduce polymyxin synthesis by the SC2-M1 strain. Chromatin immunoprecipitation assay with sequencing (ChIP-seq) revealed that most enriched pathway was that of carbohydrate metabolism. Additionally, electromobility shift assays (EMSA) confirmed the direct interaction between MsmR1 and the promoter regions of <italic>oppC3</italic>, <italic>sucA</italic>, <italic>sdr3</italic>, <italic>pepF</italic>, <italic>yycN</italic>, <italic>PPSC2_23180</italic>, <italic>pppL</italic>, and <italic>ydfp</italic>. MsmR1 stimulates polymyxin biosynthesis by directly binding to the promoter regions of <italic>oppC3</italic> and <italic>sdr3</italic>, while also directly regulating <italic>sucA</italic> and influencing the citrate cycle (TCA cycle). In addition, MsmR1 directly activates <italic>pepF</italic> and was beneficial for spore and biofilm formation. These results indicated that MsmR1 could regulate carbohydrate and amino acid metabolism, and indirectly affect biological processes such as polymyxin synthesis, biofilm formation, and motility. Moreover, MsmR1 could be autoregulated. Hence, this study expand the current knowledge of MsmR1 and will be beneficial for the application of <italic>P. polymyxa</italic> SC2 in the biological control against the certain pathogens in pepper.</p>