Inducible knockdown of Mycobacterium smegmatis MSMEG_2975 (glyoxalase II) affected bacterial growth, antibiotic susceptibility, biofilm, and transcriptome.

Tuberculosis (TB) causes millions of deaths each year across the globe. Multiple drug-resistant (MDR) and extensively drug-resistant (XDR) mycobacterial strains have made the treatment extremely difficult. To overcome this hurdle, the development of new drug targets and an effective treatment strategy are desperately needed. This can be achieved by deciphering the role of essential genes and enzymes which are involved in cell survival. One such enzyme is glyoxalase II. The glyoxalase system (glyoxalase I and glyoxalase II) has a pivotal role in cellular survival and detoxification by converting methylglyoxal (MG) into lactate. Otherwise, the increased concentration of MG then modifies DNA, proteins, and lipids, resulting in abnormalities and cell death. Interestingly, the function and physiological role of glyoxalase II have remained undetermined in mycobacteria. In this study, the functional activity of MSMEG_2975 (putative glyoxalase II) after heterologous cloning and expression was determined. And the knockdown strain Mycobacterium smegmatis KD for MSMEG_2975 was constructed with tetracycline-inducible vector pMIND. The inducible knockdown of MSMEG_2975 affected bacterial growth, biofilm formation, transcriptome, and enhanced the susceptibility to antibiotics. This work represents mycobacterial glyoxalase II as a potential drug target against mycobacterial pathogens and indicates the crucial regulatory role of glyoxalase II in mycobacteria.