Transcriptome Analysis Reveals the Potential Mechanism of MAP34-B Targeting Pasteurella multocida

<i>Pasteurella multocida</i> is a widespread zoonotic pathogen responsible for substantial economic losses in the poultry industry. The antimicrobial peptide MAP34-B has been shown to exhibit potent antibacterial activity against <i>Pasteurella multocida,</i> while the mechanism of action remains unclear. To elucidate the antibacterial mechanism of MAP34-B, we performed transcriptomic profiling via RNA sequencing (RNA-seq) on clinical strain HB03 treated with or without 47.4 µM MAP34-B for one hour. The results showed that, after treatment with MAP34-B, 281 differentially expressed genes were identified, including 161 upregulated genes and 120 downregulated genes. KEGG pathway enrichment analysis revealed that the Ribosome pathway had the highest proportion of affected genes. After treatment with MAP34-B, the gene expressions of <i>rps2</i>, <i>rps3</i>, <i>rps9</i>, <i>rps16</i>, <i>rpl3</i>, <i>rpl9</i>, <i>rpl22</i>, and <i>rpl23</i> were upregulated, which may affect bacterial protein synthesis. Additionally, the expression levels of membrane-associated genes, such as <i>SecE</i>, <i>SecG</i>, <i>lolB</i>, and <i>ompR</i>, were also altered, indicating disruption of bacterial membrane integrity. Thus, the antibacterial activity of MAP34-B against <i>Pasteurella multocida</i> primarily involves impairment of cell membrane integrity and inhibition of protein synthesis, providing a theoretical foundation for its potential application in treating bacterial infections.