“Candidatus Gortzia shahrazadis”, a Novel Endosymbiont of Paramecium multimicronucleatum and a Revision of the Biogeographical Distribution of Holospora-Like Bacteria

Serra, Valentina; Fokin, Sergei I.; Castelli, Michele; Basuri, Charan Kumar; Nitla, Venkatamahesh; Verni, Franco; Sandeep, B. V.; Kalavati, C.; Petroni, Giulio

doi:10.3389/fmicb.2016.01704

Cited by 42 publications

(42 citation statements)

References 78 publications

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“…chlorelligerum occupies basal position, thus forming a separate lineage. “ Candidatus Gortzia infectiva”, an Holospora -like bacterium, is confirmed as the closest relative of Holospora genus [23, 99]. …”

Section: Discussionmentioning

confidence: 99%

Rare Freshwater Ciliate Paramecium chlorelligerum Kahl, 1935 and Its Macronuclear Symbiotic Bacterium “Candidatus Holospora parva”

et al. 2016

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Ciliated protists often form symbioses with many diverse microorganisms. In particular, symbiotic associations between ciliates and green algae, as well as between ciliates and intracellular bacteria, are rather wide-spread in nature. In this study, we describe the complex symbiotic system between a very rare ciliate, Paramecium chlorelligerum, unicellular algae inhabiting its cytoplasm, and novel bacteria colonizing the host macronucleus. Paramecium chlorelligerum, previously found only twice in Germany, was retrieved from a novel location in vicinity of St. Petersburg in Russia. Species identification was based on both classical morphological methods and analysis of the small subunit rDNA. Numerous algae occupying the cytoplasm of this ciliate were identified with ultrastructural and molecular methods as representatives of the Meyerella genus, which before was not considered among symbiotic algae. In the same locality at least fifteen other species of “green” ciliates were found, thus it is indeed a biodiversity hot-spot for such protists. A novel species of bacterial symbionts living in the macronucleus of Paramecium chlorelligerum cells was morphologically and ultrastructurally investigated in detail with the description of its life cycle and infection capabilities. The new endosymbiont was molecularly characterized following the full-cycle rRNA approach. Furthermore, phylogenetic analysis confirmed that the novel bacterium is a member of Holospora genus branching basally but sharing all characteristics of the genus except inducing connecting piece formation during the infected host nucleus division. We propose the name “Candidatus Holospora parva” for this newly described species. The described complex system raises new questions on how these microorganisms evolve and interact in symbiosis.

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Section: Discussionmentioning

confidence: 99%

Rare Freshwater Ciliate Paramecium chlorelligerum Kahl, 1935 and Its Macronuclear Symbiotic Bacterium “Candidatus Holospora parva”

et al. 2016

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“…In a recent review of the distribution of Holospora species including H. caryophila (Serra et al, 2016), the authors list the countries with positive reports: Austria, Czech Republic, Germany, Italy, Russia, Ukraine, and USA. The here employed naïve P. biaurelia strains derive from different European regions as well as countries in Asia and Australia (Table 1), thus they do not overlap with the known incidence of H. caryophila (with the exception of Russia).…”

Section: Discussionmentioning

confidence: 99%

Fitness Impact of Obligate Intranuclear Bacterial Symbionts Depends on Host Growth Phase

et al. 2016

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According to text book definition, parasites reduce the fitness of their hosts whereas mutualists provide benefits. But biotic and abiotic factors influence symbiotic interactions, thus under certain circumstances parasites can provide benefits and mutualists can harm their host. Here we addressed the question which intrinsic biotic factors shape a symbiosis and are crucial for the outcome of the interaction between the obligate intranuclear bacterium Holospora caryophila (Alphaproteobacteria; Rickettsiales) and its unicellular eukaryotic host Paramecium biaurelia (Alveolata; Ciliophora). The virulence of H. caryophila, i.e., the negative fitness effect on host division and cell number, was determined by growth assays of several P. biaurelia strains. The performances of genetically identical lines either infected with H. caryophila or symbiont-free were compared. Following factors were considered as potentially influencing the outcome of the interaction: (1) host strain, (2) parasite strain, and (3) growth phases of the host. All three factors revealed a strong effect on the symbiosis. In presence of H. caryophila, the Paramecium density in the stationary growth phase decreased. Conversely, a positive effect of the bacteria during the exponential phase was observed for several host × parasite combinations resulting in an increased growth rate of infected P. biaurelia. Furthermore, the fitness impact of the tested endosymbionts on different P. biaurelia lines was not only dependent on one of the two involved strains but distinct for the specific combination. Depending on the current host growth phase, the presence of H. caryophila can be harmful or advantageous for P. biaurelia. Thus, under the tested experimental conditions, the symbionts can switch from the provision of benefits to the exploitation of host resources within the same host population and a time-span of less than 6 days.

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“…Boscaro et al recently have reported a new genus of HLB, Candidatus Gortzia, which is evidently a sister taxon to the genus Holospora (Boscaro et al 2013). The genus currently includes two species, Сandidatus Gortzia infectiva (Boscaro et al 2013), and Сandidatus G. shahrazadis (Serra et al 2016), macronuclear symbionts of P. jenningsi and P. multimicronucleatum, respectively. The sequences of their 16S rRNA gene differ by 9.1-9.7% from the 16S rRNA of Holospora species.…”

Section: Introductionmentioning

confidence: 99%

New intranuclear symbiotic bacteria from macronucleus ofParamecium putrinum—CandidatusGortzia yakutica

Beliavskaia

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et al. 2020

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Holospora-like bacteria are obligate intracellular Alphaproteobacteria, inhabiting nuclei of Paramecium ciliates and other protists. Alphaproteobacteria have drawn significant attention, as both closest existing relatives of bacteria that gave rise to mitochondria, as well as a class of intracellular bacteria with numerous important pathogens. HLB clade includes two genera -Holospora (Hafkine 1980) and candidatus Gortzia (Boscaro 2013). These bacteria have a peculiar life cycle with two morphological forms, a strict specificity to the host species and the type of nucleus they inhabit.Here we describe a new species of HLB -candidatus Gortzia yakutica sp. nov., a symbiont from macronucleus of Paramecium putrinum, the first known HLB for this Paramecium species. The new symbiont shows morphological similarities with other HLB. The phylogenetic analysis of SSU rDNA gene places it into candidatus Gortzia clade.

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“Candidatus Gortzia shahrazadis”, a Novel Endosymbiont of Paramecium multimicronucleatum and a Revision of the Biogeographical Distribution of Holospora-Like Bacteria

Cited by 42 publications

References 78 publications

Rare Freshwater Ciliate Paramecium chlorelligerum Kahl, 1935 and Its Macronuclear Symbiotic Bacterium “Candidatus Holospora parva”

Rare Freshwater Ciliate Paramecium chlorelligerum Kahl, 1935 and Its Macronuclear Symbiotic Bacterium “Candidatus Holospora parva”

Fitness Impact of Obligate Intranuclear Bacterial Symbionts Depends on Host Growth Phase

New intranuclear symbiotic bacteria from macronucleus ofParamecium putrinum—CandidatusGortzia yakutica

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