title: Dynamic reorganization of photosystem II supercomplexes in response to variations in light intensities.
abstract: Plants are sessile organisms and need to acclimate to ever-changing light conditions in order to survive. These changes trigger a dynamic reorganization of the membrane protein complexes in the thylakoid membranes. Photosystem II (PSII) and its light harvesting system (LHCII) are the major target of this acclimation response, and accumulating evidences indicate that the amount and composition of PSII-LHCII supercomplexes in thylakoids are dynamically adjusted in response to changes in light intensity and quality. In this study, we characterized the PSII-LHCII supercomplexes in thylakoid membranes of pea plants in response to long-term acclimation to different light intensities. We provide evidence of a reorganization of the PSII-LHCII supercomplexes showing distinct changes in their antenna moiety. Mass spectrometry analysis revealed a specific reduction of Lhcb3, Lhcb6 and M-LHCII trimers bound to the PSII cores, while the Lhcb4.3 isoform increased in response to high light intensities. The modulation of Lhcb protein content correlates with the reduction of the functional PSII antenna size. These results suggest that the Lhcb3, Lhcb4.3 and Lhcb6 antenna subunits are major players in modulation of the PSII antenna size upon long-term acclimation to increased light levels. PsbS was not detected in the isolated PSII-LHCII supercomplexes at any light condition, despite an increased accumulation in thylakoids of high light acclimated plants, suggesting that PsbS is not a constitutive component of PSII-LHCII supercomplexes.
authors.affiliation: Applied Science and Technology Department-BioSolar Lab, Politecnico di Torino, Viale T. Michel 5, 15121, Alessandria, Italy; Department of Biology, University of Padova, Via Ugo Bassi 58 B, 35121 Padova, Italy.
authors.forename: Pascal
authors.initials: P
authors.lastname: Albanese
authors.affiliation: ISALIT-Department of Science and Technological Innovation, University of Eastern Piedmont, Viale T. Michel 11, 15121 Alessandria, Italy; Department of Science and Technological Innovation, University of Eastern Piedmont, Viale T. Michel 11, 15121 Alessandria, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Manfredi
authors.affiliation: Department of Biology, University of Padova, Via Ugo Bassi 58 B, 35121 Padova, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Meneghesso
authors.affiliation: Department of Science and Technological Innovation, University of Eastern Piedmont, Viale T. Michel 11, 15121 Alessandria, Italy.
authors.forename: Emilio
authors.initials: E
authors.lastname: Marengo
authors.affiliation: Center for Space Human Robotics IIT@POLITO, Istituto Italiano di Tecnologia, Corso Trento 21, 10129, Turin, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Saracco
authors.affiliation: Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK.
authors.forename: James
authors.initials: J
authors.lastname: Barber
authors.affiliation: Department of Biology, University of Padova, Via Ugo Bassi 58 B, 35121 Padova, Italy.
authors.forename: Tomas
authors.initials: T
authors.lastname: Morosinotto
authors.affiliation: Applied Science and Technology Department-BioSolar Lab, Politecnico di Torino, Viale T. Michel 5, 15121, Alessandria, Italy. Electronic address: cristina.pagliano@polito.it.
authors.forename: Cristina
authors.initials: C
authors.lastname: Pagliano
mesh_terms: D000064:Acclimatization / Q000502:physiology; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D013058:Mass Spectrometry / Q000379:methods; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D010944:Plants / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism
chemical_list: D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex
keywords: Light acclimation; PSII–LHCII supercomplex; Photosystem II; Proteomics; SWATH analysis; Thylakoids