Myths and Facts on Sucrose Hydrolysis

VARGAS WA; MARTIN ML ; SALERNO GL

Sucrose. Properties, Biosynthesis and Health Implications

Nova Publisher

Lugar: New York; Año: 2013; p. 155 - 169

Sucrose plays an essential role in Nature aspart of the CO2 assimilation pathway in the biosphere. In plants, sucrose is important for the allocation of carbon resources, and participatesin a regulatory network that coordinates metabolism and development. Its metabolismis coordinated with the expression of photosynthesis-related genes by afeed-back regulation, and a sugar signaling pathway. Also, sucrose isaccumulated in response to environmental stresses and its degradation has beenassociated with a high demand of carbon and energy in sink tissues. In the lastdecades, several studies on sucrose degradation in plants brought to lightnovel trails on carbon trafficking and the metabolic paths leading to theregulation of gene expression. However, recent findings point to an intricaterelationship between sucrose metabolism and the whole plant physiology. Thisreview is focused on the elusive Alkaline/Neutral-Invertase (A/N-Inv) isoforms.These enzymes have been long believed as cytosol-exclusive proteins that hydrolyzethe disaccharide for general or maintenance functions in plant cells.Nevertheless, the story has changed in the last few years when novelsubcellular localizations and essential functions have been demonstrated forA/N-Invs. From being neglected as unimportant proteins, these enzymes becameleading actors in sucrose catabolism with significant roles in rootmorphogenesis, photosynthetic apparatus biosynthesis, and abiotic stressadaptation. The aim of this review article is to present a detailed and updateddiscussion of the most significant findings on the physiological properties ofA/N-Invs. Also, we incorporate this group of invertases into the metabolicpaths leading sucrose into the different circuits that govern carbonpartitioning, storage and regulation of whole plant metabolism.