FIG. 3.

Diversification in rvh T4SS architecture across the major lineages of Rickettsiales. The schematic at the top depicts the deletion and duplication events that possibly occurred prior to the split of the major Rickettsiales lineages (corresponding to the yellow box at the root of the cladogram). The color scheme for the rvh components is consistent throughout the figure and reflects the five islets (A to E) of the Rickettsia rvh P-T4SS described previously (55). The cladogram is simplified from data obtained by phylogeny estimation across 31 rvh P-T4SSs (see Fig. S1 in the supplemental material). Colored boxes in the cladogram depict deviations from the ancestral rvh P-T4SS and are explained at the bottom. Synteny maps (shaded inset) are shown for select taxa. Note that in Rickettsiales other than Rickettsia spp., rvhB9a, rvhB8a, and rvhB7 are removed from islet C. Also, multiple rvhB2 orthologs per genome are depicted, with corresponding numbers in parentheses.