Strict cospeciation of devescovinid flagellates and Bacteroidales ectosymbionts in the gut of dry-wood termites (Kalotermitidae)
Article first published online: 23 OCT 2009
© 2009 Society for Applied Microbiology and Blackwell Publishing Ltd
Special Issue: Symbiosis. Editors: Professors Paola Bonfante, Karen Visick, and Moriya Ohkuma
Volume 12, Issue 8, pages 2120–2132, August 2010
How to Cite
Desai, M. S., Strassert, J. F. H., Meuser, K., Hertel, H., Ikeda-Ohtsubo, W., Radek, R. and Brune, A. (2010), Strict cospeciation of devescovinid flagellates and Bacteroidales ectosymbionts in the gut of dry-wood termites (Kalotermitidae). Environmental Microbiology, 12: 2120–2132. doi: 10.1111/j.1462-2920.2009.02080.x
- Issue published online: 4 AUG 2010
- Article first published online: 23 OCT 2009
- Received 16 May, 2009; accepted 24 August, 2009.
The surface of many termite gut flagellates is colonized with a dense layer of bacteria, yet little is known about the evolutionary relationships of such ectosymbionts and their hosts. Here we investigated the molecular phylogenies of devescovinid flagellates (Devescovina spp.) and their symbionts from a wide range of dry-wood termites (Kalotermitidae). From species-pure flagellate suspensions isolated with micropipettes, we obtained SSU rRNA gene sequences of symbionts and host. Phylogenetic analysis showed that the Devescovina spp. present in many species of Kalotermitidae form a monophyletic group, which includes also the unique devescovinid flagellate Caduceia versatilis. All members of this group were consistently associated with a distinct lineage of Bacteroidales, whose location on the cell surface was confirmed by fluorescence in situ hybridization. The well-supported congruence of the phylogenies of devescovinids and their ectosymbionts documents a strict cospeciation. In contrast, the endosymbionts of the same flagellates (‘Endomicrobia’) were clearly polyphyletic and must have been acquired independently by horizontal transfer from other flagellate lineages. Also the Bacteroidales ectosymbionts of Oxymonas flagellates present in several Kalotermitidae belonged to several distantly related lines of descent, underscoring the general perception that the evolutionary history of flagellate–bacteria symbioses in the termite gut is complex.