Abstract
Peroxisomes play an important role in several metabolic pathways such as photorespiration in photosynthetic tissues. To clarify the correlation between peroxisome function and the localization in leaf mesophyll cell of Arabidopsis, we have isolated several peup (peroxisome unusual positioning) mutants. Here, we have focused on peup2 and peup4. Different from wild type, a part of leaf peroxisomes are aggregated at bottom of the cell in peup2, whereas many peroxisomes are flow in cytosol away from chloroplasts in peup4. Additionally, number of peroxisomes is increased in both peup2 and peup4. Analyses of EM images showed the presence of electronic high-density region in peroxisomes of these mutants. Furthermore, LSM images showed that aggregated-peroxisomes formed filamentous structure. In plant growth analyses, peup4 showed leaf damage under high-light condition. The damaged-plant resulted in accumulation of NBT and reduced photosynthetic efficiency. These defects are suppressed under high CO2 condition. Taken together with these results, maintenance of peroxisome function is discussed.
