First Ultrastructural and Molecular Phylogenetic Evidence from the Blastogregarines, an Early Branching Lineage of Plesiomorphic Apicomplexa

Publication date: Available online 23 April 2018 Source:Protist Author(s): Timur G. Simdyanov, Gita G. Paskerova, Andrea Valigurová, Andrei Diakin, Magdaléna Kováčiková, Joseph Schrével, Laure Guillou, Andrey A. Dobrovolskij, Vladimir V. Aleoshin Blastogregarines are poorly studied parasites of polychaetes superficially resembling gregarines, but lacking syzygy and gametocyst stages in the life cycle. Furthermore, their permanent multinuclearity and gametogenesis by means of budding considerably distinguish them from other parasitic Apicomplexa such as coccidians and haematozoans. The affiliation of blastogregarines has been uncertain: different authors considered them highly modified gregarines, an intermediate apicomplexan lineage between gregarines and coccidians, or an isolated group of eukaryotes altogether. Here, we report the ultrastructure of two blastogregarine species, Siedleckia nematoides and Chattonaria mesnili and provide the first molecular data on their phylogeny based on SSU, 5.8S, and LSU rDNA sequences. Morphological analysis reveals that blastogregarines possess both gregarine and coccidian features. Several traits shared with archigregarines likely represent the ancestral states of the corresponding cell structures for parasitic apicomplexans: a distinctive tegument structure and myzocytotic feeding with a well-developed apical complex. Unlike gregarines but similar to coccidians however, the nuclei of male blastogregarine gametes are ass...
Source: Protist - Category: Molecular Biology Source Type: research