appraisal of the banded and paracrystalline cytoplasmic inclusions induced in cymbidium mosaic potexvirus- and odontoglossum ringspot tobamovirus infected orchid cells using confocal laser scanning microscopy

The cymbidium mosaic potexvirus (CyMV) banded inclusions and the odontoglossum ringspot tobamovirus (ORSV) paracrystalline inclusions were studied in flowers and leaves of nine orchid cultivars using the confocal laser scanning microscope. The inclusions varied in length and width and were mostly located adjacent to the cell walls. Some ORSV inclusions fully extended across entire infected cells. We propose that the CyMV banded inclusion was formed from virus aggregates which aligned as periodical stacked layers, appearing as cross bands. The virus aggregates were folded into flexible inclusions, giving rise to various shapes and forms. The ORSV paracrystalline inclusions were observed as needle-like crystals. The confocal laser scanning microscope is an effective tool for the study of the three-dimensional structures of plant virus induced inclusions.