The gibberellin biosynthetic genes AtKAO1 and AtKAO2 have overlapping roles throughout Arabidopsis development

• DOI: 10.1111/tpj.12648
• Publication Date: 2014-08-21T16:30:03Z
• Authors: Thomas Regnault; Jean‐Michel Davière; Dimitri Heintz; Theo Lange; Patrick Achard
• Keywords: 0301 basic medicine; Arabidopsis Proteins; [SDV]Life Sciences [q-bio]; Arabidopsis; [SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology; Germination; Gene Expression Regulation, Enzymologic; Gibberellins; Mixed Function Oxygenases; 03 medical and health sciences; Phenotype; Gene Expression Regulation, Plant; Mutation

SummaryEnt‐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.