Photosynthetic antenna size in higher plants is controlled by the plastoquinone redox state at the post-transcriptional rather than transcriptional level.
We analyze the effect of the plastoquinone redox state on the regulation of the light-harvesting antenna size at transcriptional and post-transcriptional levels. This was approached by studying transcription and accumulation of light-harvesting complexes in wild type versus the barley mutant viridis zb63, which is depleted in photosystem I and where plastoquinone is constitutively reduced. We show that the mRNA level of genes encoding antenna proteins is almost unaffected in the mutant; this stability of messenger level is not a peculiarity of antenna-encoding genes, but it extends to all photosynthesis-related genes. In contrast, analysis of protein accumulation by two-dimensional PAGE shows that the mutant undergoes strong reduction of its antenna size, with individual gene products having different levels of accumulation. We conclude that the plastoquinone redox state plays an important role in the long term regulation of chloroplast protein expression. However, its modulation is active at the post-transcriptional rather than transcriptional level.
LGBP, UMR 6191 CEA-CNRS-Université de la Méditerranée, Marseille 13288, France.
Sara
S
Frigerio
Chiara
C
Campoli
Simone
S
Zorzan
Luca Isaia
LI
Fantoni
Cristina
C
Crosatti
Friedel
F
Drepper
Wolfgang
W
Haehnel
Luigi
L
Cattivelli
Tomas
T
Morosinotto
Roberto
R
Bassi
D002736:Chloroplasts / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D001467:Hordeum / Q000378:metabolism*; D007525:Isoelectric Focusing; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D010084:Oxidation-Reduction; D010788:Photosynthesis; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism; D010971:Plastoquinone / Q000737:chemistry*; D040901:Proteomics / Q000379:methods; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism; D014158:Transcription, Genetic
D045342:Light-Harvesting Protein Complexes; D010940:Plant Proteins; D012333:RNA, Messenger; D010971:Plastoquinone