Abstract
Purified preparations of grapevine fanleaf virus consist of three serologically indistinguishable centrifugal components, T, M and B, with sedimentation coefficients of 50, 86 and 120S respectively, and containing 0, 30 and 42% RNA. At equilibrium in CsCl gradients, T, M and B components precipitate. Their buoyant densities are 1.31, 1.41 and 1.49 g/ml, respectively. Infectivity is associated mostly with B component. RNA is single-stranded and occurs as two species with mol. wt. of 1.4 x 106 (RNA-2) and 2.4 x 106 (RNA-1). M particles contain only RNA-2 whereas B particles contain both species. RNA-2 is non-infective, some infectivity is associated with preparations of RNA-1, and infectivity can increase tenfold when RNA-1 and RNA-2 are mixed. The capsid contains a single protein species with mol. wt. of about 54000. Comparable data for arabis mosaic and raspberry mosaic viruses are similar. The present cryptogram of grapevine fanleaf virus is R/1:2.4/42 + 1.4/30:S/S:S/Ne.