title: Functional and transcriptional characterization of a barley mutant with impaired photosynthesis.
abstract: Chemical mutagenesis induces variations that may assist in the identification of targets for adaptation to growth under atmospheric CO2 enrichment. The aim of this work was to characterize the limitations causing reduced photosynthetic capacity in G132 mutagenized barley (Hordeum vulgare L. cv. Graphic) grown in a glasshouse. Compared to the wild type (WT) G132 showed increased transcript levels for the PSII light harvesting complex, but lower levels of chlorophyll, transcripts for protochlorophyllide oxidoreductase A and psbQ, and PSII quantum efficiency in young leaves. Rubisco limitation had an overriding influence on G132 photosynthesis, and was due to strong and selective decreases in Rubisco protein and activity. These reductions were accompanied by enhanced Rubisco transcripts, but increased levels of a Rubisco degradation product. G132 showed lower levels of carbohydrates, amino acids and corresponding transcripts, and proteins, but not of nitrate. Many of the measured parameters recovered in the mutant as development progressed, or decreased less than in the WT, indicating that senescence was delayed. G132 had a longer growth period than the WT and similar final plant dry matter. The reduced resource investment in Rubisco of G132 may prove useful for studies on barley adaptation to elevated CO2 and climate change.
authors.affiliation: Institute of Natural Resources and Agrobiology of Salamanca, IRNASA-CSIC, Cordel de Merinas 40, E-37008 Salamanca, Spain; IRTA (Institute for Food and Agricultural Research and Technology), Field Crops, Av. Alcalde Rovira i Roure, 191, E-25198 Lérida, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Córdoba
authors.affiliation: IRTA (Institute for Food and Agricultural Research and Technology), Field Crops, Av. Alcalde Rovira i Roure, 191, E-25198 Lérida, Spain.
authors.forename: José-Luis
authors.initials: JL
authors.lastname: Molina-Cano
authors.affiliation: Institute of Natural Resources and Agrobiology of Salamanca, IRNASA-CSIC, Cordel de Merinas 40, E-37008 Salamanca, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Martínez-Carrasco
authors.affiliation: Institute of Natural Resources and Agrobiology of Salamanca, IRNASA-CSIC, Cordel de Merinas 40, E-37008 Salamanca, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: Morcuende
authors.affiliation: Institute of Natural Resources and Agrobiology of Salamanca, IRNASA-CSIC, Cordel de Merinas 40, E-37008 Salamanca, Spain. Electronic address: pilar.perez@irnasa.csic.es.
authors.forename: Pilar
authors.initials: P
authors.lastname: Pérez
mesh_terms: D050260:Carbohydrate Metabolism; D002734:Chlorophyll / Q000378:metabolism; D005453:Fluorescence; D001467:Hordeum / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D009154:Mutation; D009584:Nitrogen / Q000378:metabolism; D010788:Photosynthesis; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger; D002734:Chlorophyll; D009584:Nitrogen
keywords: Gene expression; Hordeum vulgare; Mutagenesis; Photosynthesis; Primary metabolism; Rubisco