title: Arabidopsis thylakoid formation 1 is a critical regulator for dynamics of PSII-LHCII complexes in leaf senescence and excess light.
abstract: In higher plants, photosystem II (PSII) is a large pigment-protein supramolecular complex composed of the PSII core complex and the plant-specific peripheral light-harvesting complexes (LHCII). PSII-LHCII complexes are highly dynamic in their quantity and macro-organization to various environmental conditions. In this study, we reported a critical factor, the Arabidopsis Thylakoid Formation 1 (THF1) protein, which controls PSII-LHCII dynamics during dark-induced senescence and light acclimation. Loss-of-function mutations in THF1 lead to a stay-green phenotype in pathogen-infected and senescent leaves. Both LHCII and PSII core subunits are retained in dark-induced senescent leaves of thf1, indicative of the presence of PSII-LHCII complexes. Blue native (BN)-polyacrylamide gel electrophoresis (PAGE) and immunoblot analysis showed that, in dark- and high-light-treated thf1 leaves, a type of PSII-LHCII megacomplex is selectively retained while the stability of PSII-LHCII supercomplexes significantly decreased, suggesting a dual role of THF1 in dynamics of PSII-LHCII complexes. We showed further that THF1 interacts with Lhcb proteins in a pH-dependent manner and that the stay-green phenotype of thf1 relies on the presence of LHCII complexes. Taken together, the data suggest that THF1 is required for dynamics of PSII-LHCII supramolecular organization in higher plants.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Huang
authors.forename: Qingbo
authors.initials: Q
authors.lastname: Chen
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhu
authors.forename: Fenghong
authors.initials: F
authors.lastname: Hu
authors.forename: Lingang
authors.initials: L
authors.lastname: Zhang
authors.forename: Zhaoxue
authors.initials: Z
authors.lastname: Ma
authors.forename: Zuhua
authors.initials: Z
authors.lastname: He
authors.forename: Jirong
authors.initials: J
authors.lastname: Huang
mesh_terms: D017360:Arabidopsis / Q000254:growth & development* / Q000382:microbiology / Q000528:radiation effects* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D003624:Darkness; D004843:Epistasis, Genetic; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010788:Photosynthesis / Q000528:radiation effects; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D018515:Plant Leaves / Q000254:growth & development* / Q000382:microbiology / Q000528:radiation effects; D011485:Protein Binding / Q000528:radiation effects; D055550:Protein Stability / Q000528:radiation effects; D044224:Pseudomonas syringae / Q000502:physiology / Q000528:radiation effects; D020524:Thylakoids / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D029681:Arabidopsis Proteins; D045342:Light-Harvesting Protein Complexes; D008565:Membrane Proteins; D045332:Photosystem II Protein Complex; C512069:THF1 protein, Arabidopsis; D002734:Chlorophyll
keywords: Arabidopsis.; light regulation; photosynthesis; physiology of plant growth