PALE‐GREEN LEAF 1, a rice cpSRP54 protein, is essential for the assembly of the PSI‐LHCI supercomplex
Peng Gao,
Haoqiang Xia,
Qiang Li,
Zongzhu Li,
Chun Zhai,
Lin Weng,
Hualing Mi,
Song Yan,
Raju Datla,
Hua Wang,
Jun Yang
Affiliations
Peng Gao
Saskatoon Research and Development Centre Agriculture and Agri‐food Canada Saskatoon SK Canada
Haoqiang Xia
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology Chinese Academy of Sciences Shanghai China
Qiang Li
National Key Laboratory of Crop Genetic Improvement Huazhong Agricultural University Wuhan China
Zongzhu Li
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology Chinese Academy of Sciences Shanghai China
Chun Zhai
Saskatoon Research and Development Centre Agriculture and Agri‐food Canada Saskatoon SK Canada
Lin Weng
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology Chinese Academy of Sciences Shanghai China
Hualing Mi
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology Chinese Academy of Sciences Shanghai China
Song Yan
Rice Research Institute Jiangxi Academy of Agricultural Sciences Nanchang China
Raju Datla
Global Institute for Food Security University of Saskatchewan Saskatoon SK Canada
Hua Wang
State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro‐products, Institute of Virology and Biotechnology Zhejiang Academy of Agricultural Sciences Hangzhou China
Jun Yang
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology Chinese Academy of Sciences Shanghai China
Abstract Although photosynthetic multiprotein complexes have received major attention, our knowledge about the assembly of these proteins into functional complexes in plants is still limited. In the present study, we have identified a chlorophyll‐deficient mutant, pale‐green leaf 1 (pgl1), in rice that displays abnormally developed chloroplasts. Map‐based cloning of this gene revealed that OsPGL1 encodes a chloroplast targeted protein homologous to the 54‐kDa subunit of the signal recognition particle (cpSRP54). Immunoblot analysis revealed that the accumulation of the PSI core proteins PsaA and PsaB, subunits from the ATP synthase, cytochrome, and light‐harvesting complex (LHC) is dramatically reduced in pgl1. Blue native gel analysis of thylakoid membrane proteins showed the existence of an extra band in the pgl1 mutant, which located between the dimeric PSII/PSI‐LHCI and the monomeric PSII. Immunodetection after 2D separation indicated that the extra band consists of the proteins from the PSI core complex. Measurements of chlorophyll fluorescence at 77 K further confirmed that PSI, rather than PSII, was primarily impaired in the pgl1 mutant. These results suggest that OsPGL1 might act as a molecular chaperone that is required for the efficient assembly and specific integration of the peripheral LHCI proteins into the PSI core complex in rice.
