title: Antisense inhibition of the PsbX protein affects PSII integrity in the higher plant Arabidopsis thaliana.
abstract: 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.
authors.affiliation: Department of Chemistry, Umeå University, Sweden.
authors.forename: José G
authors.initials: JG
authors.lastname: García-Cerdán
authors.forename: Dmitry
authors.initials: D
authors.lastname: Sveshnikov
authors.forename: David
authors.initials: D
authors.lastname: Dewez
authors.forename: Stefan
authors.initials: S
authors.lastname: Jansson
authors.forename: Christiane
authors.initials: C
authors.lastname: Funk
authors.forename: Wolfgang P
authors.initials: WP
authors.lastname: Schröder
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D016373:DNA, Antisense / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D016373:DNA, Antisense; D018744:DNA, Plant; D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; C464795:PsbX protein, Arabidopsis