Symbiosis between the dinoflagellate genus Symbiodinium and various invertebrates and protists is an ubiquitous phenomenon in shallow tropical and subtropical waters. Molecular studies undertaken on cnidarian symbionts revealed the presence of several distinctive lineages or subgeneric clades of Symbiodinium whose taxonomic level provides limited information about the specificity between invertebrate hosts and their symbionts. This contrasts with the finding of several Symbiodinium clades being present almost exclusively in foraminifera and belonging to the subfamily Soritinae. To test whether such specificity also exists at a lower taxonomic level within Soritinae, we obtained the SSU rDNA sequences from 159 soritid individuals collected in nine localities worldwide and representing all known morphospecies of this subfamily. For each individual, the symbionts were determined either by sequencing or by RFLP analysis. We distinguished 22 phylotypes of Soritinae in relation with a number of symbiont "groups" corresponding to 3 clades and 5 subclades of Symbiodinium. Among the 22 soritid phylotypes, 14 show strict symbiont specificity and only one was found to be a host for more than two "groups" of Symbiodinium. It is suggested that the strong host-symbiont specificity observed in Soritinae is a combined effect of a selective recognition mechanism, vertical transmission of symbionts, and biogeographical isolation.
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http://dx.doi.org/10.1016/j.protis.2005.08.003 | DOI Listing |
J Eukaryot Microbiol
January 2025
Departmento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo (USP), São Paulo, SP, Brazil.
All insect trypanosomatids of the subfamily Strigomonadinae harbor a proteobacterial symbiont in their cytoplasm and unique ultrastructural cell organization. Here, we report an unexpected finding within the Strigomonadinae subfamily: the identification of a new species lacking bacterial symbiont, represented by two isolates obtained from Calliphoridae flies in Brazil and Uganda. This species is hereby designated as Kentomonas inusitatus n.
View Article and Find Full Text PDFSyst Biol
December 2024
Division of Ecology & Evolution, Research School of Biology, The Australian National University, Canberra ACT, 2600, Australia.
Orchid mycorrhizal fungi (OMF) associations in the Orchidaceae are thought to have been a major driver of diversification in the family. In the terrestrial orchid tribe Diurideae, it has long been hypothesised that OMF symbiont associations may reflect evolutionary relationships among orchid hosts. Given that recent phylogenomic efforts have been unable to fully resolve relationships among subtribes in the Diurideae, we sought to ascertain whether orchid OMF preferences may lend support to certain phylogenetic hypotheses.
View Article and Find Full Text PDFEnviron Microbiome
November 2024
Laboratory of Ecosystems and Coevolution, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501, Japan.
ISME J
January 2024
Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, United States.
Microbial symbionts associate with multicellular organisms on a continuum from facultative associations to mutual codependency. In the oldest intracellular symbioses there is exclusive vertical symbiont transmission, and co-diversification of symbiotic partners over millions of years. Such symbionts often undergo genome reduction due to low effective population sizes, frequent population bottlenecks, and reduced purifying selection.
View Article and Find Full Text PDFMicrobiol Spectr
November 2024
Department of Chemistry, Virginia Tech, Blacksburg, Virginia, USA.
Moon snails (Family: Naticidae) lay eggs using a mixture of mucus and sediment to form an egg mass commonly referred to as an egg collar. These egg collars do not appear to experience micro-biofouling or predation, and this observation led us to hypothesize that the egg collars possess a chemically rich microbiota that protect the egg collars from pathogens. Herein, we sought to gain an understanding of the bacterial composition of egg collars laid by a single species of moon snails, , by amplifying and sequencing the 16S rRNA gene from the egg collar and sediment samples collected at four distinct geographical regions in southwest Florida.
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