Host range and molecular characterization of an Iranian isolate of alfalfa mosaic virus

Alfalfa mosaic virus (AMV, Alfamovirus AMV) is the type species of the genus in the family Bromoviridae and is transmitted in non-persistent manner by aphids. Based on the previous studies, four Iranian AMV isolates collected in Khuzestan Province phylogenetically were clustered into a distinctive group. One out of the four isolates (Kh.Be.A) was selected for further studies. This isolate was biologically characterized by inoculating a range of test plants from Solanaceae, Fabaceae and Chenopodiaceae families. Among inoculated plants, AMV induced symptoms on Nicotian glutinosa L., N. debneyii L., Datura maxima L. and D. stramonium L.. In molecular studies, the total length of the P2 gene of AMV was amplified using three specific primer pairs in the RT-PCR test and sequenced to be 2418 nucleotides. Sequence comparison of the P2 gene with counterpart sequences available in the GenBank showed that the AMV isolates are classified into three groups. Members of each group were divided into two subgroups, A and B. Group IIA comprise Iranian isolates together with two Australian isolates (LC485016.1 and MK913781.1). Sequence comparison of the P2 gene of the Kh.Be.A isolate with those of the two isolates- shared 96.8 and 95% nucleotide and 96.6 and 93.7% amino acid sequence identities, respectively. According to the result of this study, phylogenetic analysis based on the P2 gene indicates three main groups of AMV isolates occurring in different countries and plant hosts.