title: An active supercomplex of NADPH dehydrogenase mediated cyclic electron flow around Photosystem I from the panicle chloroplast of Oryza sativa.
abstract: Chloroplast NAD(P)H dehydrogenase-like complex (NDH) plays a crucial role in the protection of plants against oxidative stress. In higher plants, NDH interacts with Photosystem I (PSI) to form an NDH-PSI supercomplex. However, the chloroplast supercomplex with NADPH oxidation activity remains to be identified. Here, we reported the identification of a supercomplex of NDH with NADPH-nitroblue tetrazolium oxidoreductase activity in the chloroplast of rice panicle. The active supercomplex from the panicle chloroplast contained higher amounts of the NDH subunits (NdhH, NdhK, and NdhA) than that from the flag leaf chloroplast. The highly active supercomplex might underlie the high activity of the NADPH-dependent NDH pathway and the larger proton gradient across thylakoid membranes via cyclic electron flow around PSI, as well as the higher maximal photochemical efficiency of Photosystem II at the flowering to grain-filling stage. The supercomplex is suggested to be essential for the high efficiency of photosynthesis and play a protective role in the grain formation in rice plant.
authors: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
authors: Min
authors: M
authors: Xu
authors: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
authors: Nan
authors: N
authors: Shi
authors: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
authors: Qinghua
authors: Q
authors: Li
authors: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China mihl@sippe.ac.cn.
authors: Hualing
authors: H
authors: Mi
mesh_terms: D002736:Chloroplasts / Q000378:metabolism*; D004579:Electron Transport; D004591:Electrophoresis, Polyacrylamide Gel; D009252:NADPH Dehydrogenase / Q000378:metabolism*; D012275:Oryza / Q000378:metabolism*; D045331:Photosystem I Protein Complex / Q000378:metabolism; D013050:Spectrometry, Fluorescence
chemical_list: D045331:Photosystem I Protein Complex; D009252:NADPH Dehydrogenase
keywords: 9AA-fluorescence; Chl fluorescence; NADPH dehydrogenase; Oryza sativa; chlororespiration; cyclic electron flow