Some properties of Tulare apple mosaic and ILAR viruses suggesting grouping with tobacco streak virus.

Abstract

Abstract Particle sedimentation and size in Tulare apple mosaic and some isometric labile ringspot (ILAR) viruses fulfill criteria previously suggested for grouping plant viruses with tobacco streak virus; namely, a heterogeneity in particle size but homogeneity in particle density. Such viruses apparently comprise different classes of nucleic acid with distinctive sizes and functions, encapsidated in corresponding classes of particles. On the basis of these and other criteria, recent evidence also suggests the inclusion of other quasi-isometric viruses and alfalfa mosaic virus in the group.