Biological characterization and complete genomic sequence of Apium virus Y infecting celery

A celery isolate of Apium virus Y (ApVY-Ce) from diseased plants in a commercial field in California was characterized. The experimental host range of the virus included 13 plant species in the families Apiaceae, Chenopodiaceae and Solanaceae. Almost all infected plant species showed foliar chlorosis and distortion or severe stunting and systemic chlorosis. ApVY-Ce was transmitted to all 10 host species in the Apiaceae by green peach aphids. It reacted with the potyvirus group antibody and Celery mosaic virus (CeMV) antiserum. The complete genomic sequence of ApVY-Ce was determined to be 9917 nucleotides, excluding the 3' poly(A) tail, and it comprises a large open reading frame encoding a polyprotein of 3184 amino acid residues. Its genomic organization is typical of potyviruses, and contains conserved motifs found in the genus Potyvirus. Comparisons with available genomic sequences of other potyviruses indicate that ApVY-Ce shares 26.1-52.9% identities with species of the existing genera and unassigned viruses in the Potyviridae at the polyprotein sequence level. Extensive phylogenetic analysis based on the 3'-partial sequences confirms that ApVY-Ce is most closely related to CeMV and is a distinct species of the genus Potyvirus.