• Draft Genome Sequence and Annotation of the Obligate Bacterial Endosymbiont Caedibacter taeniospiralis, Causative Agent of the Killer Phenotype in Paramecium tetraurelia.

      Zaburannyi, Nestor; Grosser, Katrin; Gasparoni, Gilles; Müller, Rolf; Schrallhammer, Martina; Simon, Martin; Helmholtz Institut für pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany. (2018-01-18)
      Caedibacter taeniospiralis is an obligate endosymbiont living in the cytoplasm of Paramecium tetraureliaC. taeniospiralis causes the so-called killer trait, eliminating intraspecific competitors of its host when released into the medium by the concerted action of the unusual protein structure R-body (refractile body) in addition to an as-yet-unknown toxin.
    • Dual-Seq reveals genome and transcriptome of Caedibacter taeniospiralis, obligate endosymbiont of Paramecium.

      Pirritano, Marcello; Zaburannyi, Nestor; Grosser, Katrin; Gasparoni, Gilles; Müller, Rolf; Simon, Martin; Schrallhammer, Martina; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (NPG, 2020-06-16)
      Interest in host-symbiont interactions is continuously increasing, not only due to the growing recognition of the importance of microbiomes. Starting with the detection and description of novel symbionts, attention moves to the molecular consequences and innovations of symbioses. However, molecular analysis requires genomic data which is difficult to obtain from obligate intracellular and uncultivated bacteria. We report the identification of the Caedibacter genome, an obligate symbiont of the ciliate Paramecium. The infection does not only confer the host with the ability to kill other cells but also renders them immune against this effect. We obtained the C. taeniospiralis genome and transcriptome by dual-Seq of DNA and RNA from infected paramecia. Comparison of codon usage and expression level indicates that genes necessary for a specific trait of this symbiosis, i.e. the delivery of an unknown toxin, result from horizontal gene transfer hinting to the relevance of DNA transfer for acquiring new characters. Prediction of secreted proteins of Caedibacter as major agents of contact with the host implies, next to several toxin candidates, a rather uncharacterized secretome which appears to be highly adapted to this symbiosis. Our data provides new insights into the molecular establishment and evolution of this obligate symbiosis and for the pathway characterization of toxicity and immunity.