title: The gibberellin biosynthetic genes AtKAO1 and AtKAO2 have overlapping roles throughout Arabidopsis development.
abstract: Ent-kaurenoic acid oxidase (KAO), a class of cytochrome P450 monooxygenases of the subfamily CYP88A, catalyzes the conversion of ent-kaurenoic acid (KA) to gibberellin (GA) GA12 , the precursor of all GAs, thereby playing an important role in determining GA concentration in plants. Past work has demonstrated the importance of KAO activity for growth in various plant species. In Arabidopsis, this enzyme is encoded by two genes designated KAO1 and KAO2. In this study, we used various approaches to determine the physiological roles of KAO1 and KAO2 throughout plant development. Analysis of gene expression pattern reveals that both genes are mainly expressed in germinating seeds and young developing organs, thus suggesting functional redundancy. Consistent with this, kao1 and kao2 single mutants are indistinguishable from wild-type plants. By contrast, the kao1 kao2 double mutant exhibits typical non-germinating GA-dwarf phenotypes, similar to those observed in the severely GA-deficient ga1-3 mutant. Phenotypic characterization and quantitative analysis of endogenous GA contents of single and double kao mutants further confirm an overlapping role of KAO1 and KAO2 throughout Arabidopsis development.
authors.affiliation: Institut de Biologie Moléculaire des Plantes, UPR2357, conventionné avec l'Université de Strasbourg, 67084, Strasbourg, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Regnault
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Davière
authors.forename: Dimitri
authors.initials: D
authors.lastname: Heintz
authors.forename: Theo
authors.initials: T
authors.lastname: Lange
authors.forename: Patrick
authors.initials: P
authors.lastname: Achard
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D018525:Germination; D005875:Gibberellins / Q000032:analysis / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010641:Phenotype
chemical_list: D029681:Arabidopsis Proteins; D005875:Gibberellins; C000601313:KAO1 proteins, Arabidopsis; C000601314:KAO2 protein, Arabidopsis; D006899:Mixed Function Oxygenases; C423619:ent-kaurenoic acid oxidase
keywords: Arabidopsis thaliana; AtKAO1; AtKAO2; CYP88A; GA biosynthesis; development; ent-kaurenoic acid oxidase; growth