title: The wheat mutant DELLA-encoding gene (Rht-B1c) affects plant photosynthetic responses to cadmium stress.
abstract: Тhe sensitivity to cadmium (Cd) stress of two near-isogenic wheat lines with differences at the Rht-B1 locus, Rht-B1a (tall wild type, encoding DELLA proteins) and Rht-B1c (dwarf mutant, encoding modified DELLA proteins), was investigated. The effects of 100 μM CdCl2on plant growth, pigment content and functional activity of the photosynthetic apparatus of wheat seedlings grown on a nutrient solution were evaluated through a combination of PAM chlorophyll fluorescence, oxygen evolution, oxidation-reduction kinetics of P700 and 77 K fluorescence. The results showed that the wheat mutant (Rht-B1c) was more tolerant to Cd stress compared to the wild type (Rht-B1a), as evidenced by the lower reductions in plant growth and pigment content, lower inhibition of photosystem I (PSI) and photosystem II (PSII) photochemistry and of the oxygen evolution measured with Clark-type and Joliot-type electrodes. Furthermore, the enhanced Cd tolerance was accompanied by increased Cd accumulation within mutant plant tissues. The molecular mechanisms through which the Rht-B1c mutation improves plant tolerance to Cd stress involve structural alterations in the mutant photosynthetic membranes leading to better protection of the Mn cluster of oxygen-evolving complex and increased capacity for PSI cyclic electron transport, protecting photochemical activity of the photosynthetic apparatus under stress. This study suggests a role for the Rht-B1c-encoded DELLA proteins in protective mechanisms and tolerance of the photosynthetic apparatus in wheat plants exposed to heavy metals stress.
authors.affiliation: Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria. Electronic address: aneli@bio21.bas.bg.
authors.forename: Anelia G
authors.initials: AG
authors.lastname: Dobrikova
authors.affiliation: Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
authors.forename: Ekaterina K
authors.initials: EK
authors.lastname: Yotsova
authors.affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), D-06466 Stadt Seeland, OT Gatersleben, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Börner
authors.affiliation: Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
authors.forename: Svetlana P
authors.initials: SP
authors.lastname: Landjeva
authors.affiliation: Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
authors.forename: Emilia L
authors.initials: EL
authors.lastname: Apostolova
mesh_terms: D002104:Cadmium / Q000493:pharmacokinetics / Q000633:toxicity*; D002338:Carotenoids / Q000378:metabolism; D002734:Chlorophyll / Q000235:genetics / Q000378:metabolism; D005453:Fluorescence; D009154:Mutation; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects / Q000235:genetics; D045331:Photosystem I Protein Complex / Q000235:genetics / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D013696:Temperature; D014908:Triticum / Q000187:drug effects* / Q000235:genetics* / Q000502:physiology
chemical_list: D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D002104:Cadmium; D002734:Chlorophyll; D002338:Carotenoids; D010100:Oxygen
keywords: Cadmium stress; Chlorophyll fluorescence; DELLA proteins; P700 photooxidation; Photochemical activity; Rht-B1c mutant