Representation of the clusters obtained in BBH for biological nitrogen fixation, bioremediation, and pathogenesis processes. Representation of the clusters obtained in BBH for each biological process. (A) BBH between symbiotic and non-symbiotic nitrogen-fixing bacteria and between nitrogen-fixing and bioremediation bacteria; (B) BBH between pathogenic bacteria; (C) the common and exclusives clusters analyzed in nitrogen-fixing bacteria, bacteria involved in bioremediation and pathogenic bacteria BBHs. (A)(B): * number of the clusters analyzed, total 96 clusters. (C): * repeat clusters obtained for NifS and FixQ. They are considered as unique NifS and unique FixQ in the analysis. (C): ** FixK was also identified in the BBH between nitrogen-fixing bacteria, but this cluster was not considered common for the bacterial analyzed because the cluster contained only one FixK present in R. tumefaciens. However, this protein was included in the FixK nitrogen-fixing cluster in phylogeny and presence and absence genes table. (C): *** Other clusters related to evolution mechanisms (not analyzed in detail).