title: Characterization of CYP115 As a Gibberellin 3-Oxidase Indicates That Certain Rhizobia Can Produce Bioactive Gibberellin A4.
abstract: The gibberellin (GA) phytohormones are produced not only by plants but also by fungi and bacteria. Previous characterization of a cytochrome P450 (CYP)-rich GA biosynthetic operon found in many symbiotic, nitrogen-fixing rhizobia led to the elucidation of bacterial GA biosynthesis and implicated GA9as the final product. However, GA9does not exhibit hormonal/biological activity and presumably requires further transformation to elicit an effect in the legume host plant. Some rhizobia that contain the GA operon also possess an additional CYP (CYP115), and here we show that this acts as a GA 3-oxidase to produce bioactive GA4from GA9. This is the first GA 3-oxidase identified for rhizobia, and provides a more complete scheme for biosynthesis of bioactive GAs in bacteria. Furthermore, phylogenetic analyses suggest that rhizobia acquired CYP115 independently of the core GA operon, adding further complexity to the horizontal gene transfer of GA biosynthetic enzymes among bacteria.
authors.affiliation: Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: Ryan S
authors.identifier: 0000-0002-2537-7010
authors.initials: RS
authors.lastname: Nett
authors.affiliation: Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: Tiffany
authors.initials: T
authors.lastname: Contreras
authors.affiliation: Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: Reuben J
authors.identifier: 0000-0003-4691-8477
authors.initials: RJ
authors.lastname: Peters
mesh_terms: D029681:Arabidopsis Proteins / Q000378:metabolism*; D005875:Gibberellins / Q000096:biosynthesis*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D012231:Rhizobium / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D005875:Gibberellins; C532593:gibberellin A4; D006899:Mixed Function Oxygenases; C000595283:gibberellin 3-oxidase 1, Arabidopsis