Fig 4. MoaR1/Rv3124 controls Mtb nitrate respiration and entry into dormancy in hypoxic conditions.

(A to C) RT-qPCR quantification of expression of Mtb moa genes (A), genes involved in nitrate transport and utilization (B), and the moaR1/rv3124 regulator (C) in H37Rv (wild-type). (D and E) RT-qPCR quantification of expression of moA genes (D) and DosR-dependent genes (E) in mutant strain inactivated in moaR1 (D,E) and in H37Rv (E). In (A-E), bacteria were cultivated in Sauton’s modified minimal medium for the indicated time periods after fast O₂ depletion before RNA extraction. In (A), solid bars indicate genes of the moaA1-D1 locus, hatched bars represent other moa genes. Data show mean±s.e.m. of technical triplicates and are representative of 5 independent experiments. In (E), statistical analysis was performed using the Student’s t test. *P<0.05; **P < 0.01; ***P < 0.001. Comparison is between the Δrv3124 mutant and the WT strain. (F to H) Nitrate utilization (F and G) and PDA accumulation in bacteria (H) cultivated in Sauton’s modified minimal medium under normoxic (F) or 14 days after fast O₂ depletion (G), or 30 days in the Wayne model (H). In (H), PDA accumulation was measured as in Fig 3D. (I) Nitrate utilization by M. kansasii (MK) or recombinant MK strains harboring the I528 cosmid with or without a moaR1/rv3124-encoding plasmid under hypoxia. (J) Survival of M. kansasii (MK) or recombinant MK strains harboring the I528 cosmid with or without a moaR1/rv3124-encoding plasmid under hypoxia. In panels (F-H), data show mean±s.e.m. of biological replicates (n = 3–4). Each biological replicate was measured in technical triplicates and statistical analyses were performed on the summary of all the biological replicates. The graphs are representative of at least 3 independent experiments. Statistical analysis was performed using the Student’s t test. *P < 0.05; **P<0.01; ***P < 0.001; ****P<0.0001.