Identification, origin, and evolution of leaf nodulating symbionts of Sericanthe (Rubiaceae)
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Bacterial leaf symbiosis is an intimate association between bacteria and plants in which endosymbionts are housed within leaf nodules. This phenomenon has been reported in three genera of Rubiaceae (Pavetta, Psychotria, and Sericanthe), but the bacterial partner has only been identified in Psychotria and Pavetta. Here we report the identification of symbiotic bacteria in two leaf nodulating Sericanthe species. Using 16S rRNA data and common housekeeping genetic markers (recA and gyrB) we studied the phylogenetic relationships of bacterial endosymbionts in Rubiaceae. Endosymbionts of leaf nodulating Rubiaceae were found to be closely related and were placed as a monophyletic group within the genus Burkholderia (β-Proteobacteria). The phylogenetic analyses revealed a pattern of strict host specificity and placed the two investigated endosymbionts at two distinct positions in the topology of the tree, suggesting at least two different evolutionary origins. The degree of sequence divergence between the Sericanthe endosymbionts and their relatives was large enough to propose the Sericanthe endosymbionts as new species (‘Candidatus Burkholderia andongensis’ and ‘Candidatus Burkholderia petitii’). In a second part of this study, the pylogenetic relationships among nodulating and non-nodulating Sericanthe species were investigated using sequence data from six chloroplast regions (rps16, trnG, trnL-trnF, petD, petA-psbJ, and atpI-atpH). Overall, genetic variation among the plastid markers was insufficient to enable phylogenetic estimation. However, our results could not rule out the possibility that bacterial leaf symbiosis originated once in a common ancestor of the Sericanthe species.
KeywordsBurkholderia endosymbionts bacterial leaf nodulation Sericanthe Rubiaceae
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- Andersson, L. 2002. Relationships and generic circumscriptions in the Psychotria complex (Rubiaceae, Psychotrieae). Syst. Geogr. Pl. 72, 167–202.Google Scholar
- Bremekamp, C.E.B. 1933. The bacteriophilous species of Psychotria. Lond. J. Bot. 71, 271–281.Google Scholar
- Gordon, J.F. 1963. The nature and distribution within the plant of the bacteria associated with certain leaf-nodulated species of the families Myrsinaceae and Rubiaceae, p. 370. Thesis. Univ. London.Google Scholar
- Lemaire B., P. de Block, S. van Oevelen, B. Verstraete, E. Smets, E. Prinsen, and S. Dessein. 2011. Identification of the bacterial endosymbionts in leaf nodulating Pavetta species (Rubiaceae). Int. J. Syst. Evol. Microbiol. (in press).Google Scholar
- Maddison, D.R. and W.P. Maddison. 2001. MacClade 4: Analysis of phylogeny and character evolution, version 4.01. Sinauer Associates, Sunderland, Massachusetts, USA.Google Scholar
- Rambaut, A. and A.J. Drummond. 2007. Tracer v1http://evolve.zoo.ox.ac.uk/software.html.
- Robbrecht, E. 1978b. Rubiaceae. Distr. Pl. Afr. 13: map 406–429.Google Scholar
- Robbrecht, E. and J.F. Manen. 2006. The major evolutionary lineages of the coffee family (Rubiaceae, angiosperms). Combined analysis (nDNA and cpDNA) to infer the position of Coptosapelta and Luculia, and supertree construction based on rbcL, rps16, trnL-trnF and atpB-rbcL data. A new classification in two subfamilies, Cinchonoideae and Rubioideae. Syst. Geogr. Pl. 76, 85–146.Google Scholar
- Tosh, J., A.P. Davis, S. Dessein, P. de Block, S. Huysmans, M.F. Fay, E. Smets, and E. Robbrecht. 2009. Phylogeny of Tricalysia (Rubiaceae) and its relationships with allied genera based on plastid DNA data: resurrection of the genus Empogona. Ann. Mossouri. Bot. Gard. 96, 194–213.CrossRefGoogle Scholar
- van Hove, C. 1972. Structure and initiation of nodules in the leaves of Neorosea andongensis (Hiern) N. Hallé. Ann. Bot. 36, 259–262.Google Scholar
- van Oevelen, S., R. de Wachter, P. Vandamme, E. Robbrecht, and E. Prinsen. 2002. Identification of the bacterial endosymbionts in leaf galls of Psychotria (Rubiaceae, angiosperms) and proposal of’ Candidatus Burkholderia kirkii’ sp. nov. Int. J. Syst. Evol. Microbiol. 52, 2023–2027.CrossRefGoogle Scholar