A gammaproteobacterial symbiont (Candidatus T. oneisti) coats (films) the surface of a marine nematode, whereas a betaproteobacterial symbiont (Alysiella filiformis) builds cellular arrays (fences) on the oral mucosa of warm-blooded vertebrates. Both rod-shaped bacteria stand upright by attaching via one of their poles to the surface of their respective hosts. Upon growth, these bacteria divide longitudinally without losing contact with one another. I will present what we have learned so far about how these host-polarized symbionts replicate and segregate their chromosomes. I will then discuss how bacterial films and fences might serve the physiology and ecology of symbionts and propose possible scenarios for their evolution.
Recent publications:
Weber, P.M., Moessel, F., Paredes, G.F., Viehboeck, T., Vischer, N.O.E., and Bulgheresi, S. (2019). A Bidimensional Segregation Mode Maintains Symbiont Chromosome Orientation toward Its Host. Curr Biol 29, 3018-3028 e3014.
Pende, N., Wang, J., Weber, P.M., Verheul, J., Kuru, E., Rittmann, S.K.R., Leisch, N., VanNieuwenhze, M.S., Brun, Y.V., den Blaauwen, T., et al. (2018). Host-Polarized Cell Growth in Animal Symbionts. Curr Biol 28, 1039-1051 e1035.
Leisch, N., Pende, N., Weber, P.M., Gruber-Vodicka, H.R., Verheul, J., Vischer, N.O., Abby, S.S., Geier, B., den Blaauwen, T., and Bulgheresi, S. (2016). Asynchronous division by non-ring FtsZ in the gammaproteobacterial symbiont of Robbea hypermnestra. Nat Microbiol 2, 16182.
Website: https://archaea.univie.ac.at/research/silvia-bulgheresi-lab/