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Figure 4 | BMC Microbiology

Figure 4

From: Phylogenetic analysis of a gene cluster encoding an additional, rhizobial-like type III secretion system that is narrowly distributed among Pseudomonas syringae strains

Figure 4

Genetic organization of the Rhc T3SS gene clusters, indicating the diversification of three main subgroups. ORFs are represented by arrows. White arrows indicate either low sequence similarities between syntenic ORFs like the PSPPH_2532: hrpO II case or ORFs not directly related to the T3SS gene clusters that were excluded from the study. Homologous ORFs are indicated by similar coloring or shading pattern. Only a few loci numbers are marked for reference. Gene symbols (N, E, J etc.) for the T3SS-2 genes are following the Hrc1 nomenclature. 1) Subgroup I cluster (Rhc-I), is represented by Bradyrizhobium japonicum USDA110 and includes also the T3SS present on the pNGR234a plasmid of strain NGR234 (not shown); 2) Subgroup II (Hrc II /Rhc II ), represented by the T3SS-II gene clusters of Rhizobium sp. NGR234 pNGR234b plasmid [38] , P. syringae pv phaseolicola 1448A[44], P. syringae pv tabaci ATCC 11528 and P. syringae pv oryzae str. 1_6 (this study, see Materials and Methods); and 3) subgroup III, represented by the sole T3SS of the Rhizobium etli CIAT652 (plasmid b) and the R. etli CNF42 plasmid d [37]. Gene products of the Hrc II /Rhc II supgroup II T3SS share greater sequence homologies with each other than with genes of subgroups I and III (Additional file 4: Table S1).

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