title: The pea SAD short-chain dehydrogenase/reductase: quinone reduction, tissue distribution, and heterologous expression.
abstract: The pea (Pisum sativum) tetrameric short-chain alcohol dehydrogenase-like protein (SAD) family consists of at least three highly similar members (SAD-A, -B, and -C). According to mRNA data, environmental stimuli induce SAD expression. The aim of this study was to characterize the SAD proteins by examining their catalytic function, distribution in pea, and induction in different tissues. In enzyme activity assays using a range of potential substrates, the SAD-C enzyme was shown to reduce one- or two-ring-membered quinones lacking long hydrophobic hydrocarbon tails. Immunological assays using a specific antiserum against the protein demonstrated that different tissues and cell types contain small amounts of SAD protein that was predominantly located within epidermal or subepidermal cells and around vascular tissue. Particularly high local concentrations were observed in the protoderm of the seed cotyledonary axis. Two bow-shaped rows of cells in the ovary and the placental surface facing the ovule also exhibited considerable SAD staining. Ultraviolet-B irradiation led to increased staining in epidermal and subepidermal cells of leaves and stems. The different localization patterns of SAD suggest functions both in development and in responses to environmental stimuli. Finally, the pea SAD-C promoter was shown to confer heterologous wound-induced expression in Arabidopsis (Arabidopsis thaliana), which confirmed that the inducibility of its expression is regulated at the transcriptional level.
authors.affiliation: Akademin för Naturvetenskap och Teknik och Centrum för Livsvetenskap , Orebro Universitet, S-70182 Orebro, Sweden.
authors.forename: Nikolai
authors.initials: N
authors.lastname: Scherbak
authors.forename: Anneli
authors.initials: A
authors.lastname: Ala-Häivälä
authors.forename: Mikael
authors.initials: M
authors.lastname: Brosché
authors.forename: Nathalie
authors.initials: N
authors.lastname: Böwer
authors.forename: Hilja
authors.initials: H
authors.lastname: Strid
authors.forename: John R
authors.initials: JR
authors.lastname: Gittins
authors.forename: Elin
authors.initials: E
authors.lastname: Grahn
authors.forename: Leif A
authors.initials: LA
authors.lastname: Eriksson
authors.forename: Åke
authors.initials: Å
authors.lastname: Strid
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D064429:Fatty Acid Synthases / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D056771:Ovule / Q000378:metabolism; D018532:Pisum sativum / Q000201:enzymology* / Q000235:genetics / Q000528:radiation effects; D019441:Plant Epidermis / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018547:Plant Stems / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics; D011401:Promoter Regions, Genetic; D011809:Quinones / Q000378:metabolism*; D013379:Substrate Specificity; D014466:Ultraviolet Rays
chemical_list: D010940:Plant Proteins; D011809:Quinones; C036543:short chain trans-2-enoyl-CoA reductase; D009247:NADH, NADPH Oxidoreductases; D064429:Fatty Acid Synthases