Open AccessThe Evolutionarily Conserved Tetratrico Peptide Repeat Protein Pale Yellow Green7 Is Required for Photosystem I Accumulation in Arabidopsis and Copurifies with the Complex
Author(s) -
Jana Stöckel,
Stefan Bennewitz,
Paul Hein,
Ralf Oelmüller
Publication year - 2006
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.106.078147
Subject(s) - arabidopsis , biology , thylakoid , mutant , photosystem , plastid , chloroplast , arabidopsis thaliana , photosystem ii , photosystem i , microbiology and biotechnology , gene , biochemistry , photosynthesis
Pale yellow green7-1 (pyg7-1) is a photosystem I (PSI)-deficient Arabidopsis (Arabidopsis thaliana) mutant. PSI subunits are synthesized in the mutant, but do not assemble into a stable complex. In contrast, light-harvesting antenna proteins of both photosystems accumulate in the mutant. Deletion of Pyg7 results in severely reduced growth rates, alterations in leaf coloration, and plastid ultrastructure. Pyg7 was isolated by map-based cloning and encodes a tetratrico peptide repeat protein with homology to Ycf37 from Synechocystis. The protein is localized in the chloroplast associated with thylakoid membranes and copurifies with PSI. An independent pyg7 T-DNA insertion line, pyg7-2, exhibits the same phenotype. pyg7 gene expression is light regulated. Comparison of the roles of Ycf37 in cyanobacteria and Pyg7 in higher plants suggests that the ancient protein has altered its function during evolution. Whereas the cyanobacterial protein mediates more efficient PSI accumulation, the higher plant protein is absolutely required for complex assembly or maintenance.