Contrasting behavior of higher plant photosystem I and II antenna systems during acclimation.
In this work we analyzed the photosynthetic apparatus in Arabidopsis thaliana plants acclimated to different light intensity and temperature conditions. Plants showed the ability to acclimate into different environments and avoid photoinhibition. When grown in high light, plants had a faster activation rate for energy dissipation (qE). This ability was correlated to higher accumulation levels of a specific photosystem II subunit, PsbS. The photosystem II antenna size was also regulated according to light exposure; smaller antenna size was observed in high light-acclimated plants with respect to low light plants. Different antenna polypeptides did not behave similarly, and Lhcb1, Lchb2, and Lhcb6 (CP24) are shown to undergo major levels of regulation, whereas Lhcb4 and Lhcb5 (CP29 and CP26) maintained their stoichiometry with respect to the reaction center in all growth conditions. The effect of acclimation on photosystem I antenna was different; in fact, the stoichiometry of any Lhca antenna proteins with respect to photosystem I core complex was not affected by growth conditions. Despite this stability in antenna stoichiometry, photosystem I light harvesting function was shown to be regulated through different mechanisms like the control of photosystem I to photosystem II ratio and the association or dissociation of Lhcb polypeptides to photosystem I.
Ballottari
Matteo
M
Dipartimento Scientifico e Tecnologico, Università di Verona, Strada Le Grazie, 15 37134 Verona, Italy.
Dall'Osto
Luca
L
Morosinotto
Tomas
T
Bassi
Roberto
R
D000064:Acclimatization; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism; D004579:Electron Transport; D008027:Light; D045342:Light-Harvesting Protein Complexes; D010455:Peptides / Q000737:chemistry; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*; D045331:Photosystem I Protein Complex / Q000502:physiology*; D045332:Photosystem II Protein Complex / Q000378:metabolism / Q000502:physiology*; D018521:Plant Physiological Phenomena; D010940:Plant Proteins / Q000378:metabolism*; D013696:Temperature; D024341:Xanthophylls / Q000378:metabolism
D029681:Arabidopsis Proteins; D045342:Light-Harvesting Protein Complexes; C489731:NPQ4 protein, Arabidopsis; D010455:Peptides; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D024341:Xanthophylls