Fine‐tuned regulation of the K+/H+ antiporter KEA3 is required to optimize photosynthesis during induction

• DOI: 10.1111/tpj.13405
• Publication Date: 2017-02-03T19:02:27Z
• Authors: Caijuan Wang; Hiroshi Yamamoto; Fumika Narumiya; Yuri Nakajima Mun...; Giovanni Finazzi; Ildiko Szabo; Toshiharu Shikanai
• Keywords: KEA3; Arabidopsis thaliana; Light; [SDV.BBM]Life Sciences [q-bio]/Biochemistry; Immunoblotting; Arabidopsis; Plant Science; Thylakoids; Disturbed proton gradient regulation mutant; Electron Transport; Potassium-Hydrogen Antiporters; 03 medical and health sciences; Gene Expression Regulation, Plant; ion antiporter; Genetics; KAE3; [SDV.BV]Life Sciences [q-bio]/Vegetal Biology; [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology; Photosynthesis; Molecular Biology; 580; 0303 health sciences; photosynthesis; Photosystem I Protein Complex; Arabidopsis Proteins; Reverse Transcriptase Polymerase Chain Reaction; K+ exchange antiporter; Arabidopsis thaliana; ion antiporter; KEA3; photosynthesis; proton motive force; Genetics; Plant Science; Cell Biology; proton motive force; Non photochemical quenching; Proton-Motive Force; Cell Biology; Plant; Carbon Dioxide; Oxygen; Phenotype; Mutation; Chlorophyll fluorescence

KEA3 is a thylakoid membrane localized K+ /H+ antiporter that regulates photosynthesis by modulating two components of proton motive force (pmf), the gradient (∆pH) and electric potential (∆ψ). We identified mutant allele KEA3, disturbed regulation (dpgr) based on its reduced non-photochemical quenching (NPQ) in artificial (CO2 -free with low O2 ) air. This phenotype was enhanced backgrounds PSI cyclic electron transport (pgr5 crr2-1). In ambient air, NPQ observed during induction dpgr, after overnight dark adaptation. contrast, knockout kea3-1 exhibited high-NPQ steady state Consistent this topology indicated efflux from lumen to stroma. The dpgr heterozygotes showed semidominant dominant respectively. protein level unaffected but downregulation activity probably disturbed. Our findings suggest fine necessary for optimizing photosynthesis.