Open AccessCharacterization of CYP115 As a Gibberellin 3-Oxidase Indicates That Certain Rhizobia Can Produce Bioactive Gibberellin A4
Author(s) -
Ryan S. Nett,
Tiffany Contreras,
Reuben J. Peters
Publication year - 2017
Publication title -
acs chemical biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.899
H-Index - 111
eISSN - 1554-8937
pISSN - 1554-8929
DOI - 10.1021/acschembio.6b01038
Subject(s) - rhizobia , gibberellin , operon , biology , bacteria , oxidase test , rhizobiaceae , biochemistry , plant hormone , biosynthesis , gene , botany , symbiosis , enzyme , genetics , escherichia coli
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 GA 9 as the final product. However, GA 9 does 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 GA 4 from GA 9 . 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.