Some Physicochemical Properties of Maize Rayado Fino Virus

Maize rayado fino virus (RFV) was purified from infected maize (Zea mays) leaves. The virus had two components: empty shells and complete virus particles with sedimentation coefficients of 54S and 120S respectively, and buoyant densities of 1.28 and 1.46 g/ml in CsCl and 1.24 and 1.37 g/ml in Cs₂SO₄. Virus particles were stable from pH 7 to pH 4 but not at pH 3. Isoelectric focusing of purified empty capsids revealed a single band in the pH range of 6 to 6.2. RFV contained 33 to 36% of single-stranded (ss)RNA of mol. wt. approx. 2 x 10⁶. Dissociated coat protein migrated in acrylamide gel electrophoresis as a main band with an average mol. wt. of 2.1 x 10⁴. RFV shares several biological and physicochemical properties with oat blue dwarf virus. These viruses appear to represent a new group of small RNA viruses, transmitted propagatively by their cicadellid vectors.