Biological and molecular characterization of Alfalfa mosaic virus infecting trumpet creeper (Campsis radicans) in Iran.
Samples of trumpet creeper (Campsis radicans) leaves showing mottling and mosaic were collected from plants growing in a private garden in Tehran province, Iran, in 2012. Symptomatic leaf samples were tested for Alfalfa mosaic virus (AMV), Cucumber mosaic virus (CMV) and Peanut stunt virus (PSV) infection in enzyme-linked immunosorbent assay (ELISA), using specific antibodies. None of the samples were positive for CMV and PSV; however, all reacted positively with that of AMV antiserum. In biological assay, systemic infection was found on Datura stramonium, Nicotiana tabacum cvs., White Burley, and Xanthi, 21 days postinoculation (DPI), while necrotic local lesions were obtained following inoculation of Phaseolus vulgaris and Vigna unguiculata within three to four DPI. Using a pair of primers specific for AMV, a DNA fragment of 880 bp was RT-PCR-amplified. Analysis of the sequences revealed the presence of 657 nucleotides of AMV complete coat protein (CP) gene (translating 218 amino acid residues). Phylogenetic analysis using neighbour-joining (NJ) method clustered AMV isolates into two main types and the IRN-Tru (GenBank Accession No. JX865593) isolate fell into type I. Pairwise nucleotide distances also confirmed two main types with the highest and lowest similarities for type I and II, respectively. The association of AMV with mosaic disease of C. radicans represents the first record from the world.