Ultrastructural Characteristics and Viral Replication Sites in Chloroplasts of Kimchi Cabbage Cells infected with Turnip Yellow Mosaic Virus

Abstract

A significant number of vesicles developed at the inner edge of chloroplasts of kimchi cabbage cells infected with turnip yellow mosaic virus (TYMV). The vesicle found in the chloroplasts are typical ultrastructures resulting from infection of TYMV. The size and shape of the vesicles varied, but most were spherical. These vesiclesserved as sites for the multiplication of virus particles, functioning as viroplasm. Additionally, a new sausage-shaped ultrastructure was observed in the chloroplasts of TYMV-infected cells. Both the sausage-shaped structures and the vesicles were composed of double membranes. TYMV utilized the space between chloroplasts as a virtual viroplasm to develop new intact virus particles. To secure the virtual viroplasm between chloroplasts, TYMV may have caused the chloroplasts to cluster together. Virus replication also occurred in viroplasms with round or half-moon shapes in the cytoplasm. Newly protruding vesicles were observed on the chloroplasts of cells infected with TYMV. No ultrastructural changes related to virus replication were observed in the mitochondria, dictyosomes or nuclei. TYMV virus particles were densely packed in the xylem vessels.

Keywords

• chloroplasts
• turnip yellow mosaic virus
• ultrastructure
• viroplasm