title: Disruption of the ndhF1 gene affects Chl fluorescence through state transition in the Cyanobacterium Synechocystis sp. PCC 6803, resulting in apparent high efficiency of photosynthesis.
abstract: In Synechocystis sp. PCC 6803, the disruption of the ndhF1 gene (slr0844), which encodes a subunit of one of the NDH-1 complexes (NDH-1L complex) serving for respiratory electron transfer, causes the largest change in Chl fluorescence induction kinetics among the kinetics of 750 disruptants searched in the Fluorome, the cyanobacterial Chl fluorescence database. The cause of the explicit phenotype of the ndhF1 disruptant was examined by measurements of the photosynthetic rate, Chl fluorescence and state transition. The results demonstrate that the defects in respiratory electron transfer obviously have great impact on Chl fluorescence in cyanobacteria. The inactivation of NDH-1L complexes involving electron transfer from NDH-1 to plastoquinone (PQ) would result in the oxidation of the PQ pool, leading to the transition to State 1, where the yield of Chl fluorescence is high. Apparently, respiration, although its rate is far lower than that of photosynthesis, could affect Chl fluorescence through the state transition as leverage. The disruption of the ndhF1 gene caused lower oxygen-evolving activity but the estimated electron transport rate from Chl fluorescence measurements was faster in the mutant than in the wild-type cells. The discrepancy could be ascribed to the decreased level of non-photochemical quenching due to state transition. One must be cautious when using the Chl fluorescence parameter to estimate photosynthesis in mutants defective in state transition.
authors: Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480 Japan.
authors: Takako
authors: T
authors: Ogawa
authors: Tetsuyuki
authors: T
authors: Harada
authors: Hiroshi
authors: H
authors: Ozaki
authors: Kintake
authors: K
authors: Sonoike
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D019069:Cell Respiration / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism*; D004579:Electron Transport / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D005453:Fluorescence; D007700:Kinetics; D008027:Light; D009154:Mutation; D009245:NADH Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000528:radiation effects; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D045331:Photosystem I Protein Complex / Q000235:genetics / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism; D010971:Plastoquinone / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D001426:Bacterial Proteins; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; C081468:NdhF protein, bacteria; D009245:NADH Dehydrogenase; D010971:Plastoquinone; D010100:Oxygen
keywords: Chl fluorescence; Cyanobacteria (Synechocystis sp. PCC 6803); NAD(P)H dehydrogenase; Photosynthesis; Respiration; State transition