[Distribution of Rubisco and RCA in Brassica chinensis chloroplasts and effect of TuMV-infection on their cellular localization].

ABSTRACT

The cellular localizations of Rubisco and Rubisco activase (RCA) in Chinese cabbage (Brassica chinensis L. cv. Suzhou) leaves were investigated by immunogold-labeling electron microscopy. The results showed that Rubisco and RCA were mainly located in chloroplasts of mesophyll, guard cell of stomatal apparatus and parenchyma of vascular bundle. A high density of gold particles were localized preferentially to the chloroplast stroma. In contrast, there were no specific binding of gold particles detected in the cytoplasm, vacuole, mitochondria and other organelles. As infected by turnip mosaic virus, the density of gold particles decreased lightly in the abnormal chloroplasts and dropped by much lower (58.44% and 64.67% as that in the health chloroplasts respectively) in swollen chloroplasts. This indicated that virus infection caused the decreases of Rubisco and RCA in host plant, which then affected plant photosynthesis.