Identification and Characterization of Genes Responsible for the Resistance of Gram-Negative Bacteria towards Nodule-Specific Cysteine Rich Peptides

Abstract

Antibiotic resistance poses a significant threat to public health, necessitating the development of alternative antimicrobial agents. Antimicrobial peptides (AMPs) have emerged as promising candidates due to their broad-spectrum activity and unique mechanisms of action. Among antimicrobial peptides, Nodule-specific Cysteine-Rich (NCR) peptides from leguminous plants exhibit potent antimicrobial properties and orchestrate Terminal Bacteroid Differentiation (TBD) in symbiotic nitrogen-fixing bacteria such as Sinorhizobium meliloti. However, the mechanisms underlying bacterial resistance to NCR peptides remain poorly understood. Here, we investigate the genetic basis of resistance to NCR247 peptide in Bradyrhizobium japonicum and Escherichia coli. We developed a transposon library in B. japonicum, enabling future exploration of cellular pathways mediating resistance to AMPs treatment. Using modern techniques like BARseq and Tn-seq, our study provides a robust framework for understanding the molecular mechanisms governing symbiotic interactions and bacterial resistance to AMPs. We also attempted to identify genes involved in polyploidy in Sinorhizobium meliloti upon NCR247 peptide treatment These findings offer insights into developing novel antimicrobial strategies and highlight the importance of investigating bacterial defense mechanisms in symbiosis.