The Phosphate-Specific Transport System Gene pstA1 Contributes to Rifampin Tolerance in Mycobacterium tuberculosis

This study investigates the role of the phosphate-specific transport system gene pstA1 in rifampin tolerance in Mycobacterium tuberculosis. We constructed a pstA1 deletion mutant (?pstA1) and demonstrated that it exhibits enhanced rifampin susceptibility compared to wild-type H37Rv. To explore the molecular mechanisms underlying this phenotype, we performed RNA-seq transcriptomic analysis comparing wild-type and ?pstA1 strains grown in standard Middlebrook 7H9 broth under exposure to sub-inhibitory rifampin (7.5 ng/ml, 1/4 MIC) for 30 or 60 minutes. The analysis revealed substantial transcriptional reprogramming in ?pstA1, providing insights into how loss of PstA1 function leads to increased rifampin susceptibility. Overall design: RNA-seq profiling of wild-type Mycobacterium tuberculosis H37Rv and ?pstA1 strains with and without rifampin treatment. Strains were cultured in Middlebrook 7H9 broth and sampled at three timepoints: untreated control (0 min), 30 minutes after sub-inhibitory rifampin exposure (7.5 ng/ml), or 60 minutes after rifampin exposure. Three biological replicates per strain per condition.