Regresar

Partial characterisation of a new virus in brusca from the Venezuelan lowlands

Abstract:

Flexuous thread-like virus particles c. 650-700 nm in length were isolated from brusca (Senna pallida) plants showing stunting, mosaic, vein yellowing and leaf malformation. The virus was mechanically transmitted to healthy Senna pallida, Cassia obovata and Cassia emarginata L. plant species. Virus particles sedimented in sucrose density gradients as one component, with a bouyant density of 1.2 g cm-3 in caesium chloride equilibrium gradients. Virions contained a molecule of ssRNA with an apparent size of 6.4 kb. The dsRNA pattern showed one main band of about 12 kb, and two subgenomic dsRNA of c. 10 and c. 5.4 kb. Analyses of purified virus preparations by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) resolved two coat protein subunits, with mol. wt of c. 28 000 and 26 000 daltons. In Western blotting the virus coat proteins reacted with an homologous polyclonal antiserum and with an antiserum to Lettuce infectious yellow virus. Electron microscopic observations of cells from infected plants showed the accumulation of cytoplasmic vesiculate inclusion bodies and crystalline aggregates of virus particles within phloem tissue. Some of the physicochemical and ultrastructural properties of this virus resemble those of a Closterovirus; however, differences show it to be sufficiently distinct from any previously reported viruses. We proposed the name of Senna chlorotic stunt (SeCSV) for this virus.