title: Elucidation of gibberellin biosynthesis in bacteria reveals convergent evolution.
abstract: Gibberellins (GAs) are crucial phytohormones involved in many aspects of plant growth and development, including plant-microbe interactions, which has led to GA production by plant-associated fungi and bacteria as well. While the GA biosynthetic pathways in plants and fungi have been elucidated and found to have arisen independently through convergent evolution, little has been uncovered about GA biosynthesis in bacteria. Some nitrogen-fixing, symbiotic, legume-associated rhizobia, including Bradyrhizobium japonicum-the symbiont of soybean-and Sinorhizobium fredii-a broad-host-nodulating species-contain a putative GA biosynthetic operon, or gene cluster. Through functional characterization of five unknown genes, we demonstrate that this operon encodes the enzymes necessary to produce GA9, thereby elucidating bacterial GA biosynthesis. The distinct nature of these enzymes indicates that bacteria have independently evolved a third biosynthetic pathway for GA production. Furthermore, our results also reveal a central biochemical logic that is followed in all three convergently evolved GA biosynthetic pathways.
authors.affiliation: Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, USA.
authors.forename: Ryan S
authors.identifier: http://orcid.org/0000-0002-2537-7010
authors.initials: RS
authors.lastname: Nett
authors.affiliation: Laboratorio de Bioorgánica, Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
authors.forename: Mariana
authors.initials: M
authors.lastname: Montanares
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, Ontario, Canada.
authors.forename: Ariana
authors.initials: A
authors.lastname: Marcassa
authors.affiliation: Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, USA.
authors.forename: Xuan
authors.initials: X
authors.lastname: Lu
authors.affiliation: Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, USA.
authors.forename: Raimund
authors.initials: R
authors.lastname: Nagel
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, Ontario, Canada.
authors.forename: Trevor C
authors.identifier: http://orcid.org/0000-0002-0344-5932
authors.initials: TC
authors.lastname: Charles
authors.affiliation: Rothamsted Research, Harpenden, Hertfordshire, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Hedden
authors.affiliation: Laboratorio de Bioorgánica, Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
authors.forename: Maria Cecilia
authors.initials: MC
authors.lastname: Rojas
authors.affiliation: Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, USA.
authors.forename: Reuben J
authors.identifier: http://orcid.org/0000-0003-4691-8477
authors.initials: RJ
authors.lastname: Peters
mesh_terms: D020369:Bradyrhizobium / Q000378:metabolism*; D019143:Evolution, Molecular; D005875:Gibberellins / Q000096:biosynthesis* / Q000737:chemistry; D008968:Molecular Conformation; D042181:Sinorhizobium fredii / Q000378:metabolism*
chemical_list: D005875:Gibberellins