TY  - JOUR
AU  - de Bianchi, S.
AU  - Betterle, N.
AU  - Kouril, R.
AU  - Cazzaniga, S.
AU  - Boekema, E.
AU  - Bassi, R.
AU  - Dall'Osto, L.
TI  - Arabidopsis Mutants Deleted in the Light-Harvesting Protein Lhcb4 Have a Disrupted Photosystem II Macrostructure and Are Defective in Photoprotection
JO  - The Plant Cell
SN  - 1040-4651
CY  - Rockville, Md.
PB  - Soc.
M1  - PreJuSER-16562
SP  - 2659 - 2679
PY  - 2011
N1  - We thank Giovanni Finazzi (Commissariat a l'Energie Atomique, Grenoble, France) for helpful discussion. Financial support for this work was provided by the Programmi di Ricerca di Interesse Nazionale (2008XB774B) and by a grant of the Italian Ministry of Research and Marie Curie Actions Initial Training Networks HARVEST (Grant 238017).
AB  - The role of the light-harvesting complex Lhcb4 (CP29) in photosynthesis was investigated in Arabidopsis thaliana by characterizing knockout lines for each of the three Lhcb4 isoforms (Lhcb4.1/4.2/4.3). Plants lacking all isoforms (koLhcb4) showed a compensatory increase of Lhcb1 and a slightly reduced photosystem II/I ratio with respect to the wild type. The absence of Lhcb4 did not result in alteration in electron transport rates. However, the kinetic of state transition was faster in the mutant, and nonphotochemical quenching activity was lower in koLhcb4 plants with respect to either wild type or mutants retaining a single Lhcb4 isoform. KoLhcb4 plants were more sensitive to photoinhibition, while this effect was not observed in knockout lines for any other photosystem II antenna subunit. Ultrastructural analysis of thylakoid grana membranes showed a lower density of photosystem II complexes in koLhcb4. Moreover, analysis of isolated supercomplexes showed a different overall shape of the C₂S₂ particles due to a different binding mode of the S-trimer to the core complex. An empty space was observed within the photosystem II supercomplex at the Lhcb4 position, implying that the missing Lhcb4 was not replaced by other Lhc subunits. This suggests that Lhcb4 is unique among photosystem II antenna proteins and determinant for photosystem II macro-organization and photoprotection.
KW  - Arabidopsis: genetics
KW  - Arabidopsis: physiology
KW  - Arabidopsis: ultrastructure
KW  - Arabidopsis Proteins: genetics
KW  - Arabidopsis Proteins: metabolism
KW  - Chlorophyll: chemistry
KW  - Chlorophyll Binding Proteins: genetics
KW  - Chlorophyll Binding Proteins: metabolism
KW  - Fluorescence
KW  - Gene Knockdown Techniques
KW  - Light
KW  - Lipid Peroxidation
KW  - Membrane Lipids: chemistry
KW  - Membrane Lipids: metabolism
KW  - Oxidation-Reduction
KW  - Oxidative Stress
KW  - Oxygen: metabolism
KW  - Photosynthesis: physiology
KW  - Photosynthetic Reaction Center Complex Proteins: genetics
KW  - Photosynthetic Reaction Center Complex Proteins: metabolism
KW  - Photosystem I Protein Complex: metabolism
KW  - Photosystem II Protein Complex: metabolism
KW  - Photosystem II Protein Complex: ultrastructure
KW  - Protein Isoforms: genetics
KW  - Protein Isoforms: metabolism
KW  - Temperature
KW  - Thylakoids: chemistry
KW  - Thylakoids: metabolism
KW  - Thylakoids: ultrastructure
KW  - Arabidopsis Proteins (NLM Chemicals)
KW  - Chlorophyll Binding Proteins (NLM Chemicals)
KW  - LHCB4.1 protein, Arabidopsis (NLM Chemicals)
KW  - Membrane Lipids (NLM Chemicals)
KW  - Photosynthetic Reaction Center Complex Proteins (NLM Chemicals)
KW  - Photosystem I Protein Complex (NLM Chemicals)
KW  - Photosystem II Protein Complex (NLM Chemicals)
KW  - Protein Isoforms (NLM Chemicals)
KW  - Chlorophyll (NLM Chemicals)
KW  - Oxygen (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:21803939
C2  - pmc:PMC3226214
UR  - <Go to ISI:>//WOS:000294164300020
DO  - DOI:10.1105/tpc.111.087320
UR  - https://juser.fz-juelich.de/record/16562
ER  -