Related Experiment Video
Updated: Oct 12, 2025
Quantification of Intracellular Growth Inside Macrophages is a Fast and Reliable Method for Assessing the Virulence of Leishmania Parasites
Published on: March 16, 2018
Analyses of Leishmania-LRV Co-Phylogenetic Patterns and Evolutionary Variability of Viral Proteins
Alexei Y Kostygov1,2, Danyil Grybchuk1,3, Yulia Kleschenko4
1Life Science Research Centre, Faculty of Science, University of Ostrava, 71000 Ostrava, Czech Republic.
Abstract:
Leishmania spp. are important pathogens causing a vector-borne disease with a broad range of clinical manifestations from self-healing ulcers to the life-threatening visceral forms. Presence of Leishmania RNA virus (LRV) confers survival advantage to these parasites by suppressing anti-leishmanial immunity in the vertebrate host. The two viral species, LRV1 and LRV2 infect species of the subgenera Viannia and Leishmania, respectively. In this work we investigated co-phylogenetic patterns of leishmaniae and their viruses on a small scale (LRV2 in L. major) and demonstrated their predominant coevolution, occasionally broken by intraspecific host switches. Our analysis of the two viral genes, encoding the capsid and RNA-dependent RNA polymerase (RDRP), revealed them to be under the pressure of purifying selection, which was considerably stronger for the former gene across the whole tree. The selective pressure also differs between the LRV clades and correlates with the frequency of interspecific host switches. In addition, using experimental (capsid) and predicted (RDRP) models we demonstrated that the evolutionary variability across the structure is strikingly different in these two viral proteins.
Insights
Leishmania RNA virus (LRV) enhances parasite survival by suppressing host immunity. This study shows LRV and its host Leishmania predominantly coevolve, with viral genes under purifying selection, indicating conserved function.
Area of Science:
- * Parasitology
- * Virology
- * Evolutionary Biology
Background:
- * Leishmania spp. are protozoan parasites causing significant human disease.
- * Leishmania RNA virus (LRV) infection provides a survival advantage to parasites by modulating host immunity.
- * LRV1 and LRV2 infect distinct Leishmania subgenera, Viannia and Leishmania, respectively.
Purpose of the Study:
- * To investigate the co-phylogenetic relationship between Leishmania and its associated viruses (LRV2 in L. major).
- * To analyze the evolutionary pressures acting on LRV genes (capsid and RNA-dependent RNA polymerase - RDRP).
- * To compare the structural variability of LRV capsid and RDRP proteins.
Main Methods:
- * Co-phylogenetic analysis of Leishmania and LRV2.
- * Selection pressure analysis on viral genes (capsid and RDRP).
- * Structural modeling (experimental for capsid, predicted for RDRP).
Main Results:
- * Predominant coevolution observed between Leishmania and LRV2, with occasional host switches.
- * Both viral genes are under purifying selection, stronger for the capsid gene.
- * Selective pressure varies across LRV clades and correlates with host switching frequency.
- * Significant differences in evolutionary variability between capsid and RDRP protein structures.
Conclusions:
- * Leishmania and LRV2 exhibit a strong coevolutionary history.
- * Purifying selection maintains the integrity of essential viral genes.
- * Host switching events can disrupt coevolutionary patterns.
- * Structural differences in viral proteins influence their evolutionary trajectories.
Related Concept Videos
01:26Size and Structure of Viral Genomes
02:54Evolutionary Relationships through Genome Comparisons