CONICET | Buscador de Institutos y Recursos Humanos

Sucrose (Suc) is one of the most abundant products in nature. Its metabolism has been studied for decades and considerable advances have been made on the understanding of its physiological role in plants. Suc biosynthesis occurs in the cytosol through the sequential action of Suc-phosphate synthase and Suc-phosphate phosphatase, and it was studied in plants, unicellular photosynthetic eukaryotes and cyanobacteria. However, it was recently demonstrated that plastids have the ability to take up Suc and metabolize it. We found in Arabidopsis and spinach that some Alkaline/Neutral Invertase (A/N-Inv) isoforms may be responsible for Suc degradation in those organelles. Based on our research, we proposed that a novel networking, involving chloroplastic A/N-Inv, would be controlling carbon trafficking between cytosol and chloroplasts. We found additional evidence showing that A/N-Inv activity directly connects Suc and starch metabolisms inside the plastids. These findings brought to light novel aspects of carbon partitioning and let us speculate that Suc plays a more intricate role controlling carbon destination within the photosynthetic cell and the whole plant.