Dynamics of the population structure and genetic variability within Iranian isolates of grapevine fanleaf virus: evidence for polyphyletic origin.

Abstract

To determine the genetic diversity and population structure of grapevine fanleaf virus (GFLV), the complete nucleotide sequence of the coat protein gene of 41 isolates from different regions in Iran was determined. Phylogenetic analyses of these isolates together with those available in the GenBank revealed two evolutionary divergent lineages, designated GFLV-G and GFLV-Ir that reflect origin of the isolates. Analysis of the genetic variability in the coat protein of these isolates revealed 37 genotype groups in GFLV population. Analyses indicate that GFLV-G and GFLV-Ir clades are significantly differentiated populations of GFLV. Also, geographical subpopulations of the virus in Iran were completely distinct from each other. Examination of nonsynonymous/synonymous nucleotide diversity showed that the CP gene has been under purifying selection. The neutrality tests indicate balancing selection operating within isolates of the northwest of Iran and purifying selection within the other populations.