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Cytology and Histology

Geminivirus-Induced Macrotubules and Their Suggested Role in Cell-to-Cell Movement. Kyung -Soo Kim, Department of Plant Pathology, University of Arkansas, Fayetteville 72701; Key-Woon Lee, Department of Agricultural Biology, College of Agriculture, Kyungpook National University, Daegu, Korea. Phytopathology 82:664-669. Accepted for publication 4 February 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/Phyto-82-664.

Ultrastructural responses of Datura stramonium (an experimental host of Euphorbia mosaic virus, a whitefly-transmitted geminivirus) were studied in situ. Cells of the earliest chlorotic lesions in mechanically inoculated leaves revealed cytopathic effects that were not observed in systemically infected leaves or in advanced lesions of inoculated leaves. These were the occurrence of macrotubules containing geminate viruslike particles in the cytoplasm and continuation of the macrotubules with the plasmodesmata. No viruslike particles occurred in the plasmodesmata of cells that were apparently without macrotubules, suggesting that the presence of the macrotubules is required for the occurrence of viruslike particles in the plasmodesmata. The nuclei of cells that had macrotubules contained characteristic nucleopathic effects of geminivirus infection, indicating that the macrotubules were virus-induced. It is suggested that the macrotubules are involved in cell-to-cell movement of the virus in early stages of infection in this host.