First Report of Alternanthera mosaic virus Infection in Angelonia in the United States

Stunting, chlorosis, and light yellow mottling resembling symptoms of nutrient deficiency were observed in angelonia (Angelonia angustifolia) in commercial production in New York. Numerous, filamentous particles 520 to 540 nm long and spherical virus particles 30 nm in diameter were observed by transmission electron microscopy (TEM) in negatively stained partially purified extracts of symptomatic Angelonia leaf tissue. Two viruses, the filamentous potexvirus Alternanthera mosaic virus (AltMV) and the spherical carmovirus Angelonia flower break virus (AnFBV) were subsequently identified on the basis of nucleotide sequence analysis of amplicons generated by reverse transcription (RT)-PCR using total RNA isolated from infected leaf tissue. A 584-bp portion of the replicase-encoding region of the AltMV genome was obtained with the degenerate primers Potex 2RC (5'-AGC ATR GNN SCR TCY TG-3') and Potex 5 (5'-CAY CAR CAR GCM AAR GAT GA-3') (3). Forward (AnFBV CP 1F-5'-AGC CTG GCA ATC TGC GTA CTG ATA-3') and reverse (AnFBV CP 1R-5'-AAT ACC GCC CTC CTG TTT GGA AGT-3') primers based on the published AnFBV genomic sequence (GenBank Accession No. NC_007733) were used to amplify a portion of the viral coat protein (CP) gene. The nucleotide sequence of the amplicon generated using the potexvirus-specific primers (GenBank Accession No. EU679362) was 99% identical to the published AltMV (GenBank Accession No. NC_007731) sequence and the nucleotide sequence of the amplicon obtained using the AnFBV CP primers was 99% identical to the published AnFBV genomic sequence (GenBank Accession No. EU679363). AnFBV occurs widely in angelonia (1) and AltMV has been identified in phlox (2). These data confirm the presence of AltMV and AnFBV in diseased angelonia plants showing stunting and nutrient deficiency-like symptoms and substantiates, to our knowledge, this first report of AltMV in angelonia in the United States.