Given the success of base editing with CTBEevolve in M. smegmatis, we sought to examine the base editing capacity of this system in M. tuberculosis. Four different spacers targeting four different endogenous sites were separately cloned into the CTBEevolve system, and the resulting editing plasmids were separately electroporated into the M. tuberculosis H37Rv competent cells. C-to-T conversion efficiencies were measured by collecting all the transformants and sequencing the target sites. Notable C-to-T conversions were observed for all the four tested sites with the editing frequencies ranging from 12% to 95% (Fig. ). Moreover, we applied this system for gene inactivation by introducing a premature stop codon into katG (Fig. ).