Study of the three-dimensional images of potyvirus-induced cytoplasmic inclusions using confocal laser scanning microscopy

The three-dimensional structure of the cytoplasmic inclusions in leaves of Cucurbita pepo L. infected with a Singapore isolate of zucchini yellow mosaic virus (ZYMV-S) was studied using a confocal laser scanning microscope. The cytoplasmic inclusions were found to be linear filamentous structures that varied in thickness and length. The formation of the inclusions probably begins when finely-pointed linear filamentous structures aggregate into bundles forming flat parallel arrays, or diverge into triangular shaped inclusions. Some cytoplasmic inclusions appeared as twisted tubules with empty central cores. The average length and width of the inclusions ranged from 9.4 ± 0.3 to 20.1 ± 0.4 μm and from 2.1 ± 0.1 to 3.7 ± 0.1 μm, respectively. Confocal laser scanning microscopy is useful for the in situ exploration of three-dimensional structures of cytoplasmic or nuclear inclusions in plant virus infected cells.