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Cytology and Histology

Ultrastructural Aspects of Tomato Golden Mosaic Virus Infection in Tobacco. A. E. Rushing, Department of Botany and Microbiology, Alabama Agricultural Experiment Station, Auburn University, Auburn 36849.; G. Sunter, W. E. Gardiner, R. R. Dute, and D. M. Bisaro. Department of Botany and Microbiology, Alabama Agricultural Experiment Station, Auburn University, Auburn 36849. Phytopathology 77:1231-1236. Accepted for publication 26 February 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-1231.

Azure A-stained tissues of Nicotiana benthamiana plants infected with the geminivirus tomato golden mosaic virus (TGMV) were studied by light microscopy. Virion aggregates were readily detected in nuclei of both phloem-associated and mesophyll cells, and this observation was confirmed and extended by transmission electron microscopy. Cytopathic effects typically observed in geminivirus-infected dicotyledonous plants were noted in phloem-associated, mesophyll, and epidermal cells and were most obvious in nuclei and chloroplasts. Nuclear changes in infected cells included dispersal of chromatin to the periphery of the organelle and the appearance of fibrillar rings. Virus particles usually were seen as large, spherical aggregates but also frequently were organized into flat sheets. The cytopathic effects of TGMV infection of N. benthamiana in many respects resemble those caused by other geminiviruses in dicotylendonous hosts. TGMV is, however, exceptional in its tissue range and in the novel manner in which virion aggregates are constructed.