TY - JOUR A1 - Fettke, Jörg A1 - Fernie, Alisdair R. T1 - Intracellular and cell-to-apoplast compartmentation of carbohydrate metabolism JF - Trends in plant science N2 - In most plants, carbohydrates represent the major energy store as well as providing the building blocks for essential structural polymers. Although the major pathways for carbohydrate biosynthesis, degradation, and transport are well characterized, several key steps have only recently been discovered. In addition, several novel minor metabolic routes have been uncovered in the past few years. Here we review current studies of plant carbohydrate metabolism detailing the expanding compendium of functionally characterized transport proteins as well as our deeper comprehension of more minor and conditionally activated metabolic pathways. We additionally explore the pertinent questions that will allow us to enhance our understanding of the response of both major and minor carbohydrate fluxes to changing cellular circumstances. Y1 - 2015 U6 - https://doi.org/10.1016/j.tplants.2015.04.012 SN - 1360-1385 VL - 20 IS - 8 SP - 490 EP - 497 PB - Elsevier CY - London ER - TY - JOUR A1 - Schopper, S. A1 - Muhlenbock, P. A1 - Sorensson, C. A1 - Hellborg, L. A1 - Lenman, M. A1 - Widell, S. A1 - Fettke, Jörg A1 - Andreasson, Erik T1 - Arabidopsis cytosolic alpha-glycan phosphorylase, PHS2, is important during carbohydrate imbalanced conditions JF - Plant biology N2 - Arabidopsis thaliana has two isoforms of alpha-glycan phosphorylase (EC 2.4.1.1), one residing in the plastid and the other in the cytosol. The cytosolic phosphorylase, PHS2, acts on soluble heteroglycans that constitute a part of the carbohydrate pool in a plant. This study aimed to define a physiological role for PHS2. Under standard growth conditions phs2 knock-out mutants do not show any clear growth phenotype, and we hypothesised that during low-light conditions where carbohydrate imbalance is perturbed, this enzyme is important. Soil-grown phs2 mutant plants developed leaf lesions when placed in very low light. Analysis of soluble heteroglycan (SHG) levels showed that the amount of glucose residues in SHG was higher in the phs2 mutant compared to wild-type plants. Furthermore, a standard senescence assay from soil-grown phs2 mutant plants showed that leaves senesced significantly faster in darkness than the wild-type leaves. We also found decreased hypocotyl extension in in vitro-grown phs2 mutant seedlings when grown for long time in darkness at 6 degrees C. We conclude that PHS2 activity is important in the adult stage during low-light conditions and senescence, as well as during prolonged seedling development when carbohydrate levels are unbalanced. KW - Lesion formation KW - low light stress conditions KW - phosphorylase KW - PHS2 KW - senescence KW - soluble heteroglycans Y1 - 2015 U6 - https://doi.org/10.1111/plb.12190 SN - 1435-8603 SN - 1438-8677 VL - 17 IS - 1 SP - 74 EP - 80 PB - Wiley-Blackwell CY - Hoboken ER -