International Journal of Systematic and Evolutionary Microbiology vol:62 issue:1 pages:202-209
Three genera in Rubiaceae (Pavetta, Psychotria and Sericanthe) harbour bacterial endosymbionts within leaf nodules or galls. The present paper identifies the bacterial endophytes in three leaf nodulating Pavetta species. In order to reveal their identity and assess their phylogenetic position, DNA data from 16S rDNA, recA and gyrB genes were sequenced from an extensive sampling of Burkholderia strains. This multigene approach results in a robust phylogeny, which places the bacterial endosymbionts of Pavetta at two distinct positions within the genus Burkholderia (β-Proteobacteria), suggesting different origins of leaf nodulated endosymbionts within Pavetta. The endophytes of the nodulated Psychotria species were recognized as closest relatives to the Pavetta endosymbionts. Our results suggest that the endosymbionts of Pavetta represent new species, which can be classified as Candidatus Burkholderia hispida, Candidatus Burkholderia rigida and Candidatus Burkholderia schumanniana.