Mìkrobìologìâ ì Bìotehnologìâ (Aug 2015)
PHYLOGENETIC HOMOLOGY OF UKRAINIAN ISOLATES OF WATERMELON MOSAIC VIRUS 2
Abstract
Aim. This work is focused on establishing phylogenetic homology of Ukrainian isolates of WMV-2 with known viral strains and isolates by comparing nucleotide sequence of the CP gene. Methods. Phylogenetic relationships of Ukrainian isolates of Watermelon mosaic virus 2, WMV 2-2g-Ukr and WMV 2-2k-Ukr (both among themselves and with other known virus strains and isolates) were estimated by comparing sequenced CP gene region. The analysis of the nucleotide sequences of sequenced amplicons (cDNA of CP gene of WMV-2) was done using MEGA 5 software. To align the nucleotide sequences, CLUSTAL W approach was used. Phylogenetic trees reflecting evolutionary relationships of studied isolates with published ones were constructed using MEGA 5 software and Maximum Likelihood (ML) method based on Tamura-Nei model. Bootstrap analysis (1000 replications) was employed for validation of the trees. Results. Phylogenetic analysis based on alignment using CLUSTAL W approach showed that the level of homology between these Ukrainian isolates reached 99,1%, indicating low degree of genome variability of the virus. The percentage of homology between Ukrainian WMV-2 isolates and strains/isolates available in the Genbank was 90,7-99%. Ukrainian WMV-2 isolates showed the highest degree of homology mostly with European isolates of this virus found in Spain, Italy and France, as well as with those strains/isolates reported from the Middle East (that may be explained by their origin). Conclusions. Basing on the obtained results we can say that the list of candidate countries from where the Ukrainian WMV-2 isolates may have originated (or where they could be brought in) is rather long and includes Spain, Italy, France as well as Iran, Turkey, Israel and Saudi Arabia. This situation may be explained by export-import trade between Ukraine and Mediterranean/Middle East countries involving the active exchange of agricultural production.
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