title: Photoinhibition in mutants of Arabidopsis deficient in thylakoid unsaturation.
abstract: Thylakoid lipid composition in higher plants is characterized by a high level of fatty acid unsaturation. We have screened four mutants of Arabidopsis that have reduced levels of fatty acid unsaturation. Three of the mutant lines tested, fad5, fad6, and the fad3-2 fad7-2 fad8 triple mutant, were more susceptible to photoinhibition than wild-type Arabidopsis, whereas one mutant, fab1, was indistinguishable from wild type. The fad3-2 fad7-2 fad8 triple mutant, which contains no trienoic fatty acids in its thylakoid membranes, was most susceptible to photoinhibition. Detailed investigation of photoinhibition in the triple mutant revealed that the rate of photoinactivation of PSII was the same in wild-type and mutant plants. However, the recovery of photoinactivated PSII was slower in fad3-2 fad7-2 fad8, relative to wild type, at all temperatures below 27 degrees C. These results indicate that trienoic fatty acids of thylakoid membrane lipids are required for low-temperature recovery from photoinhibition in Arabidopsis.
authors.affiliation: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.
authors.forename: Perumal
authors.initials: P
authors.lastname: Vijayan
authors.forename: John
authors.initials: J
authors.lastname: Browse
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D003080:Cold Temperature; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D007700:Kinetics; D008027:Light; D008034:Lincomycin / Q000494:pharmacology; D009154:Mutation; D010788:Photosynthesis / Q000502:physiology* / Q000528:radiation effects; D045322:Photosynthetic Reaction Center Complex Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000528:radiation effects; D020524:Thylakoids / Q000502:physiology* / Q000528:radiation effects
chemical_list: D005231:Fatty Acids, Unsaturated; D045322:Photosynthetic Reaction Center Complex Proteins; D008034:Lincomycin