Myxobolus pseudodispar Gorbunova, 1936 (Myxozoa) was originally described as a parasite of common roach, Rutilus rutilus (Linnaeus), with developing stages in muscles and spores disseminated in macrophage centres of different organs and tissues. Later, this parasite was described from several other cyprinids, but with relatively large intraspecific differences based on SSU rDNA gene sequences. Within our long-term study on myxozoan biodiversity, we performed a broad microscopic and molecular screening of various freshwater fish species (over 450 specimens, 36 species) from different localities. We investigated the cryptic species status of M. pseudodispar. Our analysis revealed four new unique SSU rDNA sequences of M. pseudodispar as well as an infection in new fish host species. Myxobolus pseudodispar sequence analysis showed clear phylogenetic grouping according to fish host criterion forming 13 well-recognised clades. Using 1% SSU rDNA-based genetic distance criterion, at least ten new species of Myxobolus Bütschli, 1882 may be recognised in the group of M. pseudodispar sequences. Our analysis showed the paraphyletic character of M. pseudodispar sequences and the statistical tests rejected hypothetical tree topology with the monophyletic status of the M. pseudodispar group. Myxobolus pseudodispar represents a species complex and it is a typical example of myxozoan hidden diversity phenomenon confirming myxozoans as an evolutionary very successful group of parasites with a great ability to adapt to a new hosts with subsequent speciation events.
- MeSH
- biodiverzita * MeSH
- biologická evoluce MeSH
- hostitelská specificita * MeSH
- interakce hostitele a parazita * MeSH
- Myxobolus klasifikace fyziologie MeSH
- parazitární nemoci u zvířat parazitologie MeSH
- ribozomální DNA analýza MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Myxobolus pseudodispar Gorbunova, 1936 (Myxozoa) is capable of infecting and developing mature myxospores in several cyprinid species. However, M. pseudodispar isolates from different fish show up to 5% differences in the SSU rDNA sequences. This is an unusually large intraspecific difference for myxozoans and only some of the muscle-dwelling myxozoan species possess such a high genetic variability. We intended to study the correlation between the host specificity and the phylogenetic relationship of the parasite isolates, and to find experimental proof for the putatively wide host range of M. pseudodispar with cross-infection experiments and phylogenetic analyses based on SSU rDNA. The experimental findings distinguished 'primary' and less-susceptible 'secondary' hosts. With some exceptions, M. pseudodispar isolates showed a tendency to cluster according to the fish host on the phylogenetic tree. Experimental and phylogenetic findings suggest the cryptic nature of the species. It is likely that host-shift occurred for M. pseudodispar and the parasite speciation in progress might explain the high genetic diversity among isolates which are morphologically indistinguishable.
