Evolutionary analysis of Iranian isolate of Beet mosaic virus based on Hc-Pro cistron

Several viruses infect the Beta vulgaris, among them viruses like Beet yellows virus, Beet western yellows virus and Beet mosaic virus are very common. Beet mosaic virus (BtMV), a member of genus Potyvirus, occurs in sugar beet-growing areas of the world, especially in temperate regions. Here, we presented the first molecular characterization of Iranian isolate of BtMV based on Hc-Pro cistron. Length of the HC-Pro cistron for Iranian isolate is 1371nt. Four conserved motifs KMAC, PTK, FRNK and SCCVT were identified by aligning amino acid sequence of Hc-Pro with other Potyviruses. Nucleotide pairwise comparisons of Iranian isolate with four other BtMVs (Xi, InMo, Ge and Wa) showed that the closest isolates are Xi and Ge, with 96% identity. Wa with 89% identity is very distinct from Iranian isolate. Phylogenetic trees were constructed within BtMV isolates and between other Potyviruses. In resulted trees, BtMV isolates form two main group, American isolate forms a distinct clad. Iranian and other Eurasian isolates form a sub-group. The Hc-Pro cistron sequences of BtMV isolates were checked for possible recombination events by RDP 4 package. InMo showed evidence of recombination. Hc-Pro is multifunctional protein with three main domains, Domain I, II and III. HC-Pro is multifunctional protein with three main domains, Domain I, II and III. Selection analysis showed that most of codons under selection pressure, are located at Domain I (N-terminus) and II (Central region). In domain III (C-terminus), just one codon is under selection pressure.