mDB22, a complete deletion mutant of fmt, has a growth defect compared to wt-like M. smegmatis. (a) After electroporation with pYUB412, mDB21+pYUB412 has neither Mtbfmt (top panel) nor M_Smgfmt (bottom panel). For Mtbfmt amplification, we used primers fmtTbup-do (expected product 0.75Kb), and for M_Smgfmt, primers fmtSmgup-do (0.6Kb). As seen on M. smegmatis and mDB117, the primers do not cross-react. Colony 1(*) of mDB21+pYUB412 was named mDB22, and used for further experiments. (b) Growth of mDB22 (full deletion mutant) as compared to wt-like M. smegmatis (attb:hyg, mDB16), at 37 °C. mDB22 has a small but consistent growth defect. Error bars are Standard Error of the Mean (SEM). (c) Dilution spot-plating of mDB22 (bottom) versus mDB16 (top). Despite slightly higher numbers of mDB22, the growth defect is easily seen.