Bacterial Symbiosis Maintenance in the Asexually Reproducing and Regenerating Flatworm Paracatenula galateia

Autor(en)
Ulrich Dirks, Harald Gruber-Vodicka, Nikolaus Leisch, Silvia Bulgheresi, Bernhard Egger, Peter Ladurner, Jörg Ott
Abstrakt

Bacteriocytes set the stage for some of the most intimate interactions between animal and bacterial cells. In all bacteriocyte possessing systems studied so far, de novo formation of bacteriocytes occurs only once in the host development, at the time of symbiosis establishment. Here, we present the free-living symbiotic flatworm Paracatenula galateia and its intracellular, sulfur-oxidizing bacteria as a system with previously undescribed strategies of bacteriocyte formation and bacterial symbiont transmission. Using thymidine analogue S-phase labeling and immunohistochemistry, we show that all somatic cells in adult worms - including bacteriocytes - originate exclusively from aposymbiotic stem cells (neoblasts). The continued bacteriocyte formation from aposymbiotic stem cells in adult animals represents a previously undescribed strategy of symbiosis maintenance and makes P. galateia a unique system to study bacteriocyte differentiation and development. We also provide morphological and immunohistochemical evidence that P. galateia reproduces by asexual fragmentation and regeneration (paratomy) and, thereby, vertically transmits numerous symbiont-containing bacteriocytes to its asexual progeny. Our data support the earlier reported hypothesis that the symbiont population is subjected to reduced bottleneck effects. This would justify both the codiversification between Paracatenula hosts and their Candidatus Riegeria symbionts, and the slow evolutionary rates observed for several symbiont genes.

Organisation(en)
Journal
PLOS ONE
Band
7
ISSN
1932-6203
DOI
https://doi.org/10.1371/journal.pone.0034709
Publikationsdatum
2012
Publikationsstatus
Veröffentlicht
Peer-reviewed
Ja
ÖFOS 2012
106013 Genetik
ÖFOS 2002
1407 Genetik
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/bacterial-symbiosis-maintenance-in-the-asexually-reproducing-and-regenerating-flatworm-paracatenula-galateia(312cd0ae-5431-479e-9bae-f7b9d7bcda19).html