SOME PROPERTIES OF A VIRUS-LIKE AGENT FOUND IN BRACHYPODIUM-SYLVATICUM IN THE UNITED-KINGDOM

A spherical virus-like agent (.simeq. 32 nm in diameter) was isolated from a plantof B. sylvaticum (Huds.) Beauv, growing in a botanic garden in England [UK] and showing yellow streaks in the leaves. The agent was readily purified and sedimented as a single component in sucrose density rate gradients. The particles had a sedimentation coefficient at infinite dilution of .simeq. 122S and a buoyant density of 1.35 g/cm3 in CsCl and 1.33 in Cs2SO4. The particles were stable at acid pH but above pH 7.0 in the presence of EDTA dissociated. A protein having a major polypeptide with a MW of .simeq. 3.76 .times. 104 and a species of single stranded RNA with a MW of 1.67 .times. 106 were detected in the particles. The agent was not transmitted by manual inoculation, by the insects Myzus persicae Sulzer, Rhopalosiphum padi L. or Nephotettix virescens Distant, through soil by leakage from roots or by seed. The particles had physico-chemical properties in common with tombus- and sobemoviruses but were not serologically related to 10 members of these groups or to 57 other small spherical RNA plant viruses.