|Maroon Lango, Clarissa|
Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2005
Publication Date: 5/1/2006
Citation: Adkins, S.T., Hammond, J., Gera, A., Maroon Lango, C.J., Sobolev, I., Harness, A., Zeidan, M., Spiegel, S. 2006. Biological and molecular characterization of a novel carmovirus isolated from angelonia. Phytopathology. 96:460-467. Interpretive Summary: Angelonia plants grown in commercial nurseries and garden centers in the USA and Israel were observed with flower break and mild foliar symptoms consistent with infection by a virus. The purification and characterization of a new virus species referred to as Angelonia flower break virus (AnFBV) isolated from these plants is reported. The cloning and sequencing of the viral genome and its comparison to the published sequences of other related viruses is also reported. This report initiates a cooperative virology research effort between ARS in Fort Pierce, FL and Beltsville, MD, the Agricultural Research Organization, Volcani Center in Israel and the ornamental and diagnostic industries.
Technical Abstract: A new carmovirus was isolated from Angelonia plants (Angelonia angustifolia), with flower break and mild foliar symptoms, grown in the USA and Israel. The virus, for which the name Angelonia flower break virus (AnFBV) is proposed, has isometric particles, ~30 nm in diameter. The experimental host range was limited to Nicotiana species, Schizanthus pinnatus, Myosotis sylvatica, Phlox drummondii and Digitalis purpurea. Virions were isolated from systemically infected N. benthamiana leaves, and also directly from naturally infected Angelonia leaves, using typical carmovirus protocols. Koch’s postulates were completed by mechanical inoculation of uninfected Angelonia seedlings with purified virions. Isometric particles were observed in leaf dips and virion preparations from both Angelonia and N. benthamiana, and in thin sections of Angelonia flower tissue by electron microscopy. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis of dissociated purified virus preparations, a major protein component with a molecular mass of 38 kDa was observed. Virion preparations were used to produce virus-specific polyclonal antisera in both Israel and the USA. The antisera did not react with Pelargonium flower break virus (PFBV), Carnation mottle virus (CarMV) or Saguaro cactus virus (SgCV) by either enzyme-linked immunosorbent assay or immunoblotting, and in reciprocal tests antisera against PFBV, CarMV and SgCV reacted only with the homologous viruses. The complete nucleotide sequence of a Florida isolate of AnFBV, and the coat protein (CP) gene sequences of Israeli and Maryland isolates, have been determined. The genomic RNA is 3964 nucleotides and contains four open reading frames arranged in a manner typical of carmoviruses. The AnFBV CP is most closely related to PFBV, whereas the AnFBV replicase is most closely related to PFBV, CarMV and SgCV. Particle morphology, serological properties, genome organization and phylogenetic analysis are all consistent with assignment of AnFBV to the genus Carmovirus.