Formation of light-harvesting complexes of photosystem II in Scenedesmus

Autor: Horst Senger, Riidiger Schulz, Dieter Hermsmeier
Rok vydání: 1994
Předmět:
Zdroj: Planta. 193:406-412
ISSN: 1432-2048
0032-0935
DOI: 10.1007/bf00201820
Popis: Time courses of the accumulation of chloro- phyll (Chl) a, Chl b, of mRNA transcribed from the genes encoding the Chl a/b-binding proteins of the light-har- vesting complexes (LHCs) (Lhc mRNAs) and LHC apo- proteins have been investigated in Scenedesmus wild type (WT) and the mutant C-2A' upon transfer from darkness to light. The WT develops the complete photosynthetic apparatus in darkness, whereas C-2A' exhibits a light-de- pendent formation of Chls and functional chloroplasts. Accumulation kinetics of Chls and LHC apoproteins were paralleled in green (WT) and greening (C-2A') cells. Illumination induced a steady increase in these com- pounds which was only moderate in the WT but pro- nounced in C-2A'. Accumulation of Lhc mRNAs, how- ever, was strongly enhanced by light in both WT and C-2A' cells and showed a transient time course with a maximum after 4 h illumination. Amounts of Lhc mRNAs and LHC approproteins were correlated only during the initial 4 h of greening of C-2A'. In green cells (WT and later stages of greening of C-2A'), amounts of Lhc mRNAs and LHC apoproteins diverged markedly. These findings and results provided by in-vitro transla- tion of polysomal RNA lead to the following conclusion: the light-regulation of Lhc-gene expression in Scenedes- mus takes place mainly at the transcriptional level in greening cells and at the post-translational level in green cells.
Databáze: OpenAIRE
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