Abstract
In higher plants, the balance between carbon and nitrogen nutrients must be tightly coordinated, suggesting that many biosynthetic pathways are affected by photosynthetic carbon metabolism. To clarify the effect of alteration of photosynthetic capacity on various metabolisms, we generated and evaluated the transgenic Araidopsis expressing cyanobacterial FBP/SBPase in chloroplasts (ApFS) or FBPase-II in cytosol (AcF). ApFS exhibit increased CO2 fixation capacity and final dry matter under atmospheric (360 ppm) CO2 conditions. Furthermore, the transcript level of starch synthase increased compared with wild-type plants. In ApFS plants, some metabolites involved in the Calvin cycle were increased, whereas many amino acids were decreased. AcF plants showed the phenotypes in growth, photosynthetic activity, and fresh weight similar to the wild-type plants under atmospheric conditions. In contrast, under high (1000 ppm) CO2 conditions, the lateral shoot, leaf number and fresh weight of AcF were increased compared with the wild-type plants. To clarify a cause of these phenotypes in the transgenic plants, we are analyzing transcript levels of various genes responded to plant hormones.
