Authors

AY Kostygov²; AT Albanaz²; A Butenko¹; E Gerasimov⁴; J Lukeš¹; V Yurchenko³;  ¹ Institute of Parasitology, Biology Centre, Czechia;  ² University of Ostrava, Czechia;  ³ University of Ostrava, Ostrava, Czechia;  ⁴ Lomonosov Moscow State University, Russian Federation

Discussion

The family Trypanosomatidae is an extensively studied group of flagellates parasitizing a wide range of hosts, including vertebrates, arthropods, leeches, plants, and even ciliates. The interest to this taxon is stipulated by the significant impact of human pathogens, such as Trypanosoma brucei, T. cruzi, and Leishmania spp. Trypanosomatids are categorized into monoxenous (have a single host) and dixenous (alternate between two hosts, one of which is termed a vector). Insects are the most frequent hosts of monoxenous species and commonly act as vectors for dixenous ones. In addition to practical implications, these flagellates exhibit a multitude of traits garnering research interest: polycistronic gene transcription, trans-splicing, extensive RNA editing, glycosomes, etc. Some members of the family feature additional peculiarities such as an unconventional genetic code, intracellular bacterial symbionts, or two flagella attached to each other.

The growing role of genomics has significantly influenced the advancement of the trypanosomatid studies in the last two decades. Starting from the human-pathogenic species such studies soon expanded into the area of monoxenous flagellates and dixenous plant-infecting Phytomonas spp., which allowed comparative analyses highlighting numerous lifestyle-related changes in gene repertoire.

Recently the list of the available genomic sequences has significantly increased so that at least one species from each trypanosomatid genus as well as most subgenera of trypanosomes. Based on this nearly comprehensive dataset we performed a phylogenomic inference, resulting in the clarification of previously uncertain phylogenetic relationships for a number of trypanosomatid lineages. For example, we demonstrated the paraphyly of the genus Crithidia in respect to Leptomonas and Lotmaria, relatedness of Vickermania and Jaenimonas, sister relationship of African salivarian trypanosomes with the poorly studied subgenus Squamatrypanum, parasitizing squamate reptiles and small mammals.

We offer the obtained tree as a framework to address questions on the evolution of various traits in trypanosomatids and provide examples of using it for this purpose (evolutionary distribution of the hydrogen peroxide -decomposing enzyme catalase and patterns of kinetoplast cryptogene editing).