title: Carbonylation and loss-of-function analyses of SBPase reveal its metabolic interface role in oxidative stress, carbon assimilation, and multiple aspects of growth and development in Arabidopsis.
abstract: Sedoheptulose-1,7-bisphosphatase (SBPase) is a Calvin cycle enzyme and functions in photosynthetic carbon fixation. We found that SBPase was rapidly carbonylated in response to methyl viologen (MV) treatments in detached leaves of Arabidopsis plants. In vitro activity analysis of the purified recombinant SBPase showed that SBPase was carbonylated by hydroxyl radicals, which led to enzyme inactivation in an H(2)O(2) dose-dependent manner. To determine the conformity with carbonylation-caused loss in enzymatic activity in response to stresses, we isolated a loss-of-function mutant sbp, which is deficient in SBPase-dependent carbon assimilation and starch biosynthesis. sbp mutant exhibited a severe growth retardation phenotype, especially for the developmental defects in leaves and flowers where SBPASE is highly expressed. The mutation of SBPASE caused growth retardation mainly through inhibition of cell division and expansion, which can be partially rescued by exogenous application of sucrose. Our findings demonstrate that ROS-induced oxidative damage to SBPase affects growth, development, and chloroplast biogenesis in Arabidopsis through inhibiting carbon assimilation efficiency. The data presented here provide a case study that such inactivation of SBPase caused by carbonyl modification may be a kind of adaptation for plants to restrict the operation of the reductive pentose phosphate pathway under stress conditions.
authors.affiliation: The National Key Laboratory of Plant Molecular Genetics and National Center for Plant Gene Research (Shanghai), Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
authors.forename: Xun-Liang
authors.initials: XL
authors.lastname: Liu
authors.forename: Hai-Dong
authors.initials: HD
authors.lastname: Yu
authors.forename: Yuan
authors.initials: Y
authors.lastname: Guan
authors.forename: Ji-Kai
authors.initials: JK
authors.lastname: Li
authors.forename: Fang-Qing
authors.initials: FQ
authors.lastname: Guo
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism*; D015536:Down-Regulation; D018384:Oxidative Stress; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D050050:Protein Carbonylation
chemical_list: D029681:Arabidopsis Proteins; D002244:Carbon; D010744:Phosphoric Monoester Hydrolases; C022627:sedoheptulose-bisphosphatase