|Liu, Hsing Yeh|
Submitted to: Virus Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2010
Publication Date: 9/15/2010
Citation: Xu, D., Liu, H., Koike, S.T., Li, F., Li, R. 2010. Biological characterization and complete genomic sequence of Apium virus Y infecting celery. Virus Research. 155:76-82. Interpretive Summary: Plants in the family Apiaceae are affected by many viruses, including seven viruses belonging to the genus Potyvirus. Apium virus Y (ApVY) was first found in sea celery in Australia in 2002. ApVY was first identified in the celery plants in California in 2007. Phylogenetic comparisons of the coat protein sequences did not clearly separate ApVY from Celery mosaic virus (CeMV) and Carrot virus Y (CarVY) as distinct species; however, the comparisons of the available 3’-partial sequences indicated that ApVY was distinct from others. These three potyviruses are important viral pathogens of the apiaceous crops, but their complete genome sequences have not been available. Therefore, determination of the complete genomic sequence of ApVY would be essential to discriminate it from other potyviruses as well as to advance our understanding of the potyviruses infecting the apiaceous plants. Furthermore, characterizations of biological and serological properties of ApVY would provide more information for the disease management. We report here the experimental host range, aphid transmission, serological reactions and complete genomic sequence of celery isolate of ApVY. Our results provide conclusive evidence that ApVY is a distinct species in the genus Potyvirus.
Technical Abstract: Apium virus Y (ApVY) isolated from celery plants (Ce) with ring spot and line pattern symptoms from a commercial field in California was characterized in this study. The experimental host range of the virus included 13 plant species in the families Apiaceae, Chenopodiaceae and Solanaceae, and 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 in length, 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.