Phylogeny of bacterial methylotrophy genes reveals robustness in Methylobacterium mxaF sequences and mxa operon construction

► mxaF sequence is conserved in Methylobacterium spp. compared to other genera. ► mxaF is a genetic marker for PPFMs, even when similar genes are considered. ► mxaF is a genetic marker for PPFMs, even when many bacterial genera are considered. ► A pattern was observed in Methylobacterium mxa family operon construction. ► Evidence exists for mxa horizontal gene transfer events between bacterial genera.