Comparison of the electron transport properties of the psbo1 and psbo2 mutants of Arabidopsis thaliana.
Genome sequence of Arabidopsis thaliana (Arabidopsis) revealed two psbO genes (At5g66570 and At3g50820) which encode two distinct PsbO isoforms: PsbO1 and PsbO2, respectively. To get insights into the function of the PsbO1 and PsbO2 isoforms in Arabidopsis we have performed systematic and comprehensive investigations of the whole photosynthetic electron transfer chain in the T-DNA insertion mutant lines, psbo1 and psbo2. The absence of the PsbO1 isoform and presence of only the PsbO2 isoform in the psbo1 mutant results in (i) malfunction of both the donor and acceptor sides of Photosystem (PS) II and (ii) high sensitivity of PSII centers to photodamage, thus implying the importance of the PsbO1 isoform for proper structure and function of PSII. The presence of only the PsbO2 isoform in the PSII centers has consequences not only to the function of PSII but also to the PSI/PSII ratio in thylakoids. These results in modification of the whole electron transfer chain with higher rate of cyclic electron transfer around PSI, faster induction of NPQ and a larger size of the PQ-pool compared to WT, being in line with apparently increased chlororespiration in the psbo1 mutant plants. The presence of only the PsbO1 isoform in the psbo2 mutant did not induce any significant differences in the performance of PSII under standard growth conditions as compared to WT. Nevertheless, under high light illumination, it seems that the presence of also the PsbO2 isoform becomes favourable for efficient repair of the PSII complex.
Allahverdiyeva
Yagut
Y
Department of Biology, Plant Physiology and Molecular Biology, University of Turku, Turku, Finland.
Mamedov
Fikret
F
Holmström
Maija
M
Nurmi
Markus
M
Lundin
Björn
B
Styring
Stenbjörn
S
Spetea
Cornelia
C
Aro
Eva-Mari
EM
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport / Q000528:radiation effects; D007425:Intracellular Membranes / Q000378:metabolism / Q000528:radiation effects; D007700:Kinetics; D008027:Light; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D010777:Photochemistry; D010788:Photosynthesis / Q000528:radiation effects; D045331:Photosystem I Protein Complex / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D013696:Temperature; D020524:Thylakoids / Q000378:metabolism / Q000528:radiation effects; D013997:Time Factors
D029681:Arabidopsis Proteins; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; C054266:photosystem II manganese-stabilizing protein