Abstract
When a fusion protein of cytochrome b5 and the red fluorescent protein (Cyt b5-RFP) was expressed in tobacco BY-2 cells, the expressed protein formed intracellular aggregates that emitted red fluorescence (RFP aggregate). When such cells were grown to the stationary phase, RFP fluorescence was detected in the lumen of the vacuoles and a few fluorescent punctates were found in these cells. This relocation of RFP fluorescence was caused by autophagy, which was induced by nutrient limitations. To analyze this transport is related to the development and aging of cells in plant tissues, we generated transgenic Arabidopsis plant expressing the Cyt b5-RFP. We found that RFP aggregates were present in almost all the cells in most of the tissue analyzed. We also observed that the aggregates decreased in senescing leaves and pods.
