Effects of Parsnip Yellow Fleck Virus on Plant Cells

Abstract

SUMMARY Light and electron microscopy of spinach and Nicotiana clevelandii leaf tissue infected with parsnip yellow fleck virus (PYFV) and of chervil containing PYFV either alone or together with its ‘helper’ virus, anthriscus yellows (AYV), showed that cells of all species contained inclusion bodies not found in virus-free plants. Inclusions occurred in most types of leaf cell and consisted of vesicles probably derived from the endoplasmic reticulum, other smaller vesicular structures, and straight tubules about 30 nm in diam.; mitochondria and Golgi bodies often occurred around the periphery. Older inclusion bodies were composed almost entirely of the straight tubules. Tubules about 45 nm in diam. and containing virus-like particles were often associated with the plasmodesmata and were sheathed by outgrowths of cell-wall material. Tubular structures occurred also in the sieve tubes and some of them contained virus-like particles. Most cell organelles appeared normal but many chloroplasts possessed peripheral vesicles bounded by a single membrane and some contained rectangular microcrystalline structures. No effects attributable to AYV were noted.