AUTHOR=Bailey Nicholas P. , Shao Yuxin , Du Shaodua , Foster Peter G. , Fettweis Jennifer , Hall Neil , Wang Zheng , Hirt Robert P. 

TITLE=Evolutionary conservation of Trichomonas-mycoplasma symbiosis across the host species barrier

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1242275

DOI=10.3389/fmicb.2023.1242275

ISSN=1664-302X

ABSTRACT=<sec id="sec1"><title>Introduction</title><p>The protozoan parasite <italic>Trichomonas vaginalis</italic> is the most common cellular sexually transmitted disease in humans, and the closely related species <italic>Trichomonas gallinae</italic> is an avian parasite of ecological and economic importance. Phylogenetic evidence suggests <italic>T. vaginalis</italic> arose during bird to human transmission of a <italic>T. gallinae</italic>-like ancestor. <italic>Trichomonas vaginalis</italic> shares a strong clinical association with the independent sexually transmitted pathogen <italic>Metamycoplasma</italic> (formerly <italic>Mycoplasma</italic>) <italic>hominis</italic>, and the uncultured bacterium “<italic>Candidatus</italic> Malacoplasma (formerly <italic>Mycoplasma</italic>) girerdii,” with the latter association being an order of magnitude stronger. Both bacterial species have been shown to profoundly influence <italic>T. vaginalis</italic> growth, energy production and virulence-associated mechanisms.</p></sec><sec id="sec2"><title>Methods</title><p>Evidence for a novel <italic>Malacoplasma</italic> sp. was discovered by <italic>in vivo</italic> Illumina metatranscriptomics sequencing of the <italic>T. gallinae</italic>-infected pigeon mouth. We leveraged published 16S rDNA profiling data from digestive tract of 12 healthy and 24 <italic>T. gallinae</italic>-infected pigeons to investigate association between the novel <italic>Malacoplasma</italic> sp. and <italic>T. gallinae</italic>. We utilised Illumina metagenomics sequencing targeted to pigeon oral and crop samples infected with the novel <italic>Malacoplasma</italic> sp. to generate its full-length genome sequence. Sequence similarity network analysis was used to compare annotated proteins from the novel <italic>Malacoplasma</italic> sp. with a range of other related species.</p></sec><sec id="sec3"><title>Results</title><p>Here we present evidence for a novel <italic>Malacoplasma</italic> species, related to “<italic>Ca.</italic> M. girerdii,” that is strongly associated with <italic>T. gallinae</italic> in the upper digestive tract of domestic pigeons. Analysis of the genome sequence revealed gene features apparently specific to a <italic>Trichomonas</italic>-symbiotic <italic>Malacoplasma</italic> lineage.</p></sec><sec id="sec4"><title>Discussion</title><p>These data support a model of long-term association between <italic>Trichomonas</italic> and <italic>Malacoplasma</italic> spp. that has been conserved across diversification of the <italic>Trichomonas</italic> lineage and the host species barrier from birds to human.</p></sec>