Dragset, Marte S.Barczak, AmyKannan, NishaMærk, MaliFlo, Trude H.Valla, SveinRubin, EricSteigedal, Magnus2015-10-012015Dragset, Marte S., Amy K. Barczak, Nisha Kannan, Mali Mærk, Trude H. Flo, Svein Valla, Eric J. Rubin, and Magnus Steigedal. 2015. “Benzoic Acid-Inducible Gene Expression in Mycobacteria.” PLoS ONE 10 (9): e0134544. doi:10.1371/journal.pone.0134544. http://dx.doi.org/10.1371/journal.pone.0134544.1932-6203http://nrs.harvard.edu/urn-3:HUL.InstRepos:22856864Conditional expression is a powerful tool to investigate the role of bacterial genes. Here, we adapt the Pseudomonas putida-derived positively regulated XylS/Pm expression system to control inducible gene expression in Mycobacterium smegmatis and Mycobacterium tuberculosis, the causative agent of human tuberculosis. By making simple changes to a Gram-negative broad-host-range XylS/Pm-regulated gene expression vector, we prove that it is possible to adapt this well-studied expression system to non-Gram-negative species. With the benzoic acid-derived inducer m-toluate, we achieve a robust, time- and dose-dependent reversible induction of Pm-mediated expression in mycobacteria, with low background expression levels. XylS/Pm is thus an important addition to existing mycobacterial expression tools, especially when low basal expression is of particular importance.en-USJournal Article2015-10-0110.1371/journal.pone.0134544