title: Characterization of genes encoding ABA 8'-hydroxylase in ethylene-induced stem growth of deepwater rice (Oryza sativa L.).
abstract: Ethylene and submergence enhance stem elongation of deepwater rice, at least in part, by reducing in the internode the endogenous abscisic acid (ABA) content and increasing the level of gibberellin A1 (GA1). We cloned and characterized the CYP707A5 and CYP707A6 genes, which encode putative ABA 8'-hydroxylase, the enzyme that catalyzes the oxidation of ABA. Expression of CYP707A5 was upregulated significantly by ethylene treatment, whereas that of CYP707A6 was not altered. Recombinant proteins from both genes expressed in yeast cells showed activity of ABA 8'-hydroxylase. This finding indicates that CYP707A5 may play a role in ABA catabolism during submergence- or ethylene-induced stem elongation in deepwater rice. Taken together, these results provide links between the molecular mechanisms and physiological phenomena of submergence- and ethylene-induced stem elongation in deepwater rice.
authors.affiliation: Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824-1312, USA.
authors.forename: Seung-Hwan
authors.initials: SH
authors.lastname: Yang
authors.forename: Dongsu
authors.initials: D
authors.lastname: Choi
mesh_terms: D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D006899:Mixed Function Oxygenases / Q000235:genetics*; D012275:Oryza / Q000187:drug effects / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics*; D018547:Plant Stems / Q000187:drug effects / Q000502:physiology*
chemical_list: D010940:Plant Proteins; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; C107203:abscisic acid 8'-hydroxylase