title: Regulation of alternative oxidase gene expression in soybean.
abstract: Soybean (Glycine max cv. Stevens) suspension cells were used to investigate the expression of the alternative oxidase (Aox) multigene family. Suspension cells displayed very high rates of cyanide-insensitive respiration, but Aox3 was the only isoform detected in untreated cells. Incubation with antimycin A, citrate, salicylic acid or at low temperature (10 degrees C) specifically induced the accumulation of the Aox1 isoform. Aox2 was not observed under any conditions in the cells. Increases in Aox1 protein correlated with increases in Aox1 mRNA. Treatment of soybean cotyledons with norflurazon also induced expression of Aox1. Reactive oxygen species (ROS) were detected upon incubation of cells with antimycin, salicylic acid or at low temperature, but not during incubation with citrate. Aox1 induction by citrate, but not by antimycin, was prevented by including the protein kinase inhibitor staurosporine in the medium. The results suggest that multiple pathways exist in soybean to regulate expression of Aox genes and that Aox1 specifically is induced by a variety of stress and metabolic conditions via at least two independent signal transduction pathways.
authors.affiliation: Plant Molecular Biology Group, School of Biomedical and Chemical Sciences, University of Western Australia, Crawley, Australia.
authors.forename: Ira
authors.initials: I
authors.lastname: Djajanegara
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Finnegan
authors.forename: Christel
authors.initials: C
authors.lastname: Mathieu
authors.forename: Tulene
authors.initials: T
authors.lastname: McCabe
authors.forename: James
authors.initials: J
authors.lastname: Whelan
authors.forename: David A
authors.initials: DA
authors.lastname: Day
mesh_terms: D000968:Antimycin A / Q000031:analogs & derivatives* / Q000494:pharmacology; D019343:Citric Acid / Q000494:pharmacology; D003080:Cold Temperature; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D024101:Mitochondrial Proteins; D009243:NAD / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D020156:Salicylic Acid / Q000494:pharmacology; D013025:Glycine max / Q000166:cytology / Q000201:enzymology / Q000235:genetics*; D000099188:Alternative Oxidase
chemical_list: D000968:Antimycin A; D019343:Citric Acid; D024101:Mitochondrial Proteins; D009243:NAD; D010088:Oxidoreductases; D010940:Plant Proteins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D020156:Salicylic Acid; D000099188:Alternative Oxidase; C032456:antimycin