title: LHCII can substitute for LHCI as an antenna for photosystem I but with reduced light-harvesting capacity.
abstract: Light-harvesting complexes (LHCs) are major constituents of the antenna systems in higher plant photosystems. Four Lhca subunits are tightly bound to the photosystem I (PSI) core complex, forming its outer antenna moiety called LHCI. The Arabidopsis thaliana mutant ΔLhca lacks all Lhca1-4 subunits and compensates for its decreased antenna size by binding LHCII trimers, the main constituent of the photosystem II antenna system, to PSI. In this work we have investigated the effect of LHCI/LHCII substitution by comparing the light harvesting and excitation energy transfer efficiency properties of PSI complexes isolated from ΔLhca mutants and from the wild type, as well as the consequences for plant growth. We show that the excitation energy transfer efficiency was not compromised by the substitution of LHCI with LHCII but a significant reduction in the absorption cross-section was observed. The absence of LHCI subunits in PSI thus significantly limits light harvesting, even on LHCII binding, inducing, as a consequence, a strong reduction in growth.
authors: Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, I-37134 Verona, Italy.
authors: Mauro
authors: M
authors: Bressan
authors: Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, I-37134 Verona, Italy.
authors: Luca
authors: L
authors: Dall'Osto
authors: Centre for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, via Pascoli 70/3, 20133 Milan, Italy.
authors: Ilaria
authors: I
authors: Bargigia
authors: Centre for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, via Pascoli 70/3, 20133 Milan, Italy.|IFN-CNR, Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
authors: Marcelo J P
authors: MJ
authors: Alcocer
authors: IFN-CNR, Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
authors: Daniele
authors: D
authors: Viola
authors: IFN-CNR, Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
authors: Giulio
authors: G
authors: Cerullo
authors: Centre for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, via Pascoli 70/3, 20133 Milan, Italy.|IFN-CNR, Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
authors: Cosimo
authors: C
authors: D'Andrea
authors: Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, I-37134 Verona, Italy.
authors: Roberto
authors: 0000-0002-4140-8446
authors: R
authors: Bassi
authors: Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, I-37134 Verona, Italy.
authors: Matteo
authors: 0000-0001-8410-3397
authors: M
authors: Ballottari
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D061146:Chlorophyll Binding Proteins / Q000378:metabolism*; D004735:Energy Transfer; D010788:Photosynthesis; D045331:Photosystem I Protein Complex / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D061146:Chlorophyll Binding Proteins; C490278:LHCA1 protein, Arabidopsis; C490277:Lhca2 protein, Arabidopsis; D045331:Photosystem I Protein Complex