Purification and Properties of Japanese Iris Necrotic Ring Virus, a Possible New Carmovirus.

Abstract

Japanese iris necrotic ring virus (JINRV) particles were isometric about 35nm in diameter and showed rounded outlines with rough surfaces when negatively stained in uranyl acetate. Purified virus preparations contained single component with a sedimentation coefficient of 118 S. In isopycnic centrifugation in CsCl, the particles formed a single band of buoyant density 1.353g/cm3. Nucleic acid extracted from the purified virus particles was identified as single stranded RNA by the following properties: positive orcinol reaction; susceptible to RNase A both in 1×SSC or 0.1×SSC; increase of about 18% in maximum absorption and shift of the absorption maximum to higher wavelengths by 4nm after treatment with formaldehyde (1.8%). Polyacrylamide gel electrophoresis demonstrated one nucleic acid and one coat protein with estimated molecular weights of 1.28×106 and 38, 000, respectively. An antiserum against purified virus particles with a homologous titer of 512 in Ouchterlony double diffusion tests was prepared. The virus was serologically unrelated to 10 other single component viruses with isometric particles, including tomato bushy stunt, carnation mottle, and several members of the tombusvirus and carmovirus groups. However, its other properties were similar to those of carmoviruses.