Electron microscopy of sowthistle yellow vein virus in cells of sowthistle plants

Abstract

Electron microscopy of sections of leaves ( Sonchus oleraceus L.) infected with sowthistle yellow vein virus (SYVV) showed that the virus could infect parenchyma, developing xylem, and phloem cells. Virus was found in cells of leaves showing chlorosis and vein-clearing; none was seen in the adjacent green areas. Virus was localized predominantly in the nucleus and rarely in the cytoplasm. In either location, cell organelles were not interspersed with viral aggregates, although both polysomes and endoplasmic reticulum were normally at the periphery of cytoplasmic viral aggregates. In most cells areas of the perinuclear space were enlarged to accommodate aggregates of virus particles which were often invaginated into the nucleus.