Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: March 24, 2004
Publication Date: May 21, 2004
Citation: Guaragna, M.A., Ambrose, J., Jordan, R.L. 2004. Detection and characterization of euphorbia ringspot potyvirus. American Phytopathological Society. 94:S36. Technical Abstract: Euphorbia milii var. splendens ('Crown of Thorns') is a low-growing succulent evergreen shrub with very thorny grooved stems and branches and has thick fleshy leaves. The recent development of more compact varieties in a range of colors has provided the floral industry with another popular potted plant. A commercially-grown plant exhibiting ring-shaped chlorotic spots and leaf and flower deformations was shown to contain 650-850 nm flexuous particles and tested positive for potyvirus in ELISA using our genus Potyvirus broad spectrum reacting PTY-1 monoclonal antibody. The only reported virus known to infect 'Crown of Thorns' is Euphorbia ringspot potyvirus (EuRSV). Total RNA extracts from infected leaves were used in RT-PCR assays with generic potyvirus (and, later, EuRSV-specific) primers which amplify various highly conserved 335, c.700, or c.1600bp fragments from the 3' terminus of most potyviruses which includes the potyviral coat protein (CP) and the 3' non-coding region (3'NCR). Sequence analysis of cloned amplicons revealed potyvial similarities, but less than 64% CP amino acid identity and less than 55% 3'NCR identity with any potyvirus currently in the GenBank database, including other ornamental-infecting potyviruses. Pairwise alignments and Clustal W analysis confirm the classification of this poorly described virus as a potyvirus member. Since no antisera against this virus is available, synthetic peptides and bacterially-expressed His-tagged cloned CP from this virus are under evaluation as sources of antigen for EuRSV-specific antisera production for future use in diagnosis.