Budzanіvska I. Phylogenetic analysis and strain diversity of plants RNA viruses in Ukraine - Manuscript copyright.

Thesis is describing divergence of the different RNA plant viruses in Ukraine and provides data of their molecular-biological and phylogenetic analysis. Also the origin of the analyzed ukrainian plant viruses was determined and hypothetical mechanisms of evolution for ukrainian isolates of RNA plant viruses have been tested. Study of gene sequences of capsid proteins of ten ukrainian RNA viruses (from 8 genera and 5 virus families) isolated in field and laboratory conditions confirmed no evidence for direct dependence of molecular divergence of viruses from the climate conditions, type of host plant, geographical spread or effect of abiotic factors (heavy metals). The established trend of low genetic variability of viruses, despite high mutational ability of RNA viruses, indicates the impact of negative selection to maintain the stability of viral nucleotide sequences. Analysis of the phylogenetic trees topology shows the direction of isolation and low probability for the formation of ukrainian strain with new properties. Our data have shown high genetic conservatism for most phytoviral populations that favors modern hypothesis of evolution for plant RNA viruses. High relationship level between all ukrainian isolates have been reveled, indicating their high homogeny (for all studied viruses except ВХПЛЯ)