VIEW ARTICLE

Etiology

Association of Spiral Filamentous Viruslike Particles with Rice Hoja Blanca. Francisco J. Morales, Virologist, Bean Program, Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia, Apartado Aereo 67-13; Andrea I. Niessen, research assistant, Bean Program, Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia, Apartado Aereo 67-13. Phytopathology 73:971-974. Accepted for publication 15 December 1982. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-971.

Fine, spiral, filamentous particles ~3 nm in diameter were consistently associated with hoja blanca-affected rice plants. The filamentous particles were isolated from infected plants following organic solvent clarification, concentration with polyethylene glycol, and equilibrium centrifugation in Cs₂SO₄ or CsCl gradients. Purified preparations exhibited typical nucleoprotein ultraviolet absorption spectra with a maximum at A_{260 nm} and an A_{260/280 nm} ratio of 1.4. The preparations contained one major and one minor protein of molecular weights 34 and 17.5 x 10³ daltons, respectively, as determined by SDS-PAGE. In double immunodiffusion tests, an antiserum (prepared by injecting rabbits with purified preparations) produced specific precipitin reactions with leaf extracts of hoja blanca-affected rice plants, but not with leaf extracts of healthy rice plants. No serological reaction was observed in similar tests of leaf extracts from hoja blanca-infected Echinochloa colonum.