INFECTION OF PHASEOLUS-VULGARIS BY BEAN GOLDEN MOSAIC-VIRUS - ULTRASTRUCTURAL ASPECTS

Bean golden mosaic virus, a single-stranded DNA plant virus, induced striking changes in the nuclear structure which were distinct from those known to occur in cells infected with other plant viruses. The changes, in order of occurrence, included 1) hypertrophy of the nucleolus so that it occupied up to 3 4 of the nuclear volume, 2) segregation of nucleolur components into discrete granular and fibrillar regions which were similar to those induced by certain carcinogens or antibiotics in animal cells, 3) appearance of electron dense, condensed fibrillar rings in various numbers and sizes, and 4) appearance of viruslike particles either as loosely compacted aggregates or in hexagonally close-packed arrays. Cytochemical studies revealed that the segregated nucleoli were composed mainly of ribonucleoprotein while the fibrillar rings were deoxyribonucleoprotein. Virus particles occurred only in the nuclei of infected cells. Only phloem cells showed nucleopathic effects and/or contained virus particles. © 1978.