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Antisense inhibition of the PsbX protein affects PSII integrity in the higher plant Arabidopsis Thaliana
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
Umeå University, Faculty of Science and Technology, Department of Chemistry. (Potato Research Centre, Agriculture and Agri-Food Canada, PO Box 20280, Fredericton, NB, E3B 4Z7, Canada)
Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA.
Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).ORCID iD: 0000-0002-7906-6891
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2009 (English)In: Plant and Cell Physiology, ISSN 0032-0781, E-ISSN 1471-9053, Vol. 50, no 2, 191-202 p.Article in journal (Refereed) Published
Abstract [en]

PSII, the oxygen-evolving complex of photosynthetic organisms, contains an intriguingly large number of low molecular weight proteins. PsbX, one of these proteins, is ubiquitous in PSII complexes of cyanobacteria and plants. In previous studies, deletion of the PsbX protein in cyanobacteria has not resulted in clear phenotypic changes. Here we report the construction of an antisense (AS-PsbX) line in Arabidopsis thaliana with <10% of wild-type PsbX levels. AS-PsbX plants are capable of photoautotrophic growth, but biochemical, biophysical and immunological evidence demonstrates that reduction of PsbX contents leads to reduced levels of functional assembled PSII core complexes, while the light-harvesting antennae are not affected. In addition, levels of phosphorylation of the core proteins D1, D2 and CP43 are severely reduced in the antisense plants relative to their wild-type counterparts. We conclude that PsbX is important for accumulation of functional PSII.

Place, publisher, year, edition, pages
Oxford University Press, 2009. Vol. 50, no 2, 191-202 p.
Keyword [en]
Photosystem II, Chloroplast, OJIP, Photosynthesis, PSII, Reaction centre, Thermoluminiscence, Thylakoid membrane
National Category
Biological Sciences
Research subject
URN: urn:nbn:se:umu:diva-19513DOI: 10.1093/pcp/pcn188PubMedID: 19112079OAI: diva2:201881
Available from: 2009-03-05 Created: 2009-03-05 Last updated: 2015-04-29Bibliographically approved
In thesis
1. Functions of REP27 and the low molecular weight proteins PsbX and PsbW in repair and assembly of photosystem II
Open this publication in new window or tab >>Functions of REP27 and the low molecular weight proteins PsbX and PsbW in repair and assembly of photosystem II
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]



Oxygenic photosynthesis is the major producer of both oxygen and organic compounds on earth and takes place in plants, green algae and cyanobacteria. The thylakoid membranes are the site of the photosynthetic light reactions that involve the concerted action of four major protein complexes known as photosystem II (PSII), cytochrome b6f complex, ATP synthase and photosystem I (PSI). The function of PSII is of particular interest as it performs the light–driven water splitting reaction driving the photosynthetic electron transport. My thesis addressed different aspects of PSII assembly and the functions of its low molecular weight PSII subunits PsbX and PsbW. Photosynthesis in green algae and higher plants is controlled by the nucleus. Many proteins of nuclear origin participate in the regulation of the efficient assembly of the photosynthetic protein complexes. In this investigation we have identified one of these nuclear encoded auxiliary proteins of photosystem II, REP27, which participates in the assembly of the D1 reaction center protein and repair of photodamaged PSII in the green algae Chlamydomonas reinhardtii. Interestingly, PSII is specially enriched in Low Molecular Weight (LMW) subunits that have masses less than 10kDa. These proteins account for more than the half of the PSII subunits. Several questions remains poorly understood regarding the LMW: Which is their evolutionary origin? What function do they perform in the protein complex? Where are they located in the protein structure? In this investigation the functions of two of these LMW subunits (PsbX and PsbW) have been studied using antisense inhibition and T-DNA knockout mutant plants in Arabidopsis thaliana. Deficiency of the PsbX protein leads to impaired accumulation and functionality of PSII. Characterization of PsbW knock-out plants show that PsbW participates in stabilization of the macro-organization of PSII and the peripheral antenna (Light Harvesting Complex, LHCII) in the grana stacks of the chloroplast, also known as PSII-LHCII supercomplexes.



50 p.
Photosynthesis, photosystem II reaction center, PSII-LHCII supercomplex, antisense plant, T-DNA knockout plant, auxiliary protein
Research subject
urn:nbn:se:umu:diva-19517 (URN)978-91-7264-752-7 (ISBN)
Public defence
2009-03-27, KB3B1, KBC, Umeå, 10:00 (English)
Available from: 2009-03-10 Created: 2009-03-05 Last updated: 2009-09-15Bibliographically approved

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Garcia Cerdan, Jose GinesSveshnikov, DmitryJansson, StefanFunk, ChristianeSchröder, Wolfgang
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