Distribution and genetic diversity of three apple viruses in Belarus

• Published in: Vavilovskiĭ zhurnal genetiki i selekt͡s︡ii Vol. 20; no. 5; pp. 673 - 682
• Main Authors: Kuzmitskaya, P. V., Urbanovich, O. Yu
• Format: Journal Article
• Language: English
• Published: Siberian Branch of the Russian Academy of Sciences, Federal Research Center Institute of Cytology and Genetics, The Vavilov Society of Geneticists and Breeders 01-12-2016
• Subjects: aclsv; asgv; aspv; genetic diversity; rt-pcr; selection pressure
• ISSN: 2500-0462; 2500-3259
• DOI: 10.18699/VJ16.187

Apple chlorotic leaf spot virus (ACLSV), apple stem pitting virus (ASPV), and apple stem grooving virus (ASGV) are common in all apple cultivating countries including Belarus. The aim of this investigation was to study the genetic diversity of the apple-tree viruses in Belarus. Virus-infected apple trees were identified by RT- PCR in modern horticultural plantations and were not found among old trees aged more than 50 years. The genome fragments of the ACLSV, ASPV, and ASGV viruses detected were cloned and sequenced. The analysis of their nucleotide sequences gives evidence of high molecular variability generated mostly by single nucleotide substitutions and rarely by single nucleotide deletions and insertions. Recombination processes could also make some contribution to the existing genetic diversity of the virus populations studied. Estimates of selective pressure on the genome fragments of ACLSV, ASPV and ASGV obtained in this study as well as homologous sequences from the GenBank database indicate negative selection, except for one codon in the sequence of the ACLSV coat protein, which is under positive selection. The study of phylogenetic relationships between viruses isolated in different countries did not reveal any clear-cut relationship between their geographical origin and the degree of similarity of virus genome fragments.