title: LATERAL BRANCHING OXIDOREDUCTASE acts in the final stages of strigolactone biosynthesis in Arabidopsis.
abstract: Strigolactones are a group of plant compounds of diverse but related chemical structures. They have similar bioactivity across a broad range of plant species, act to optimize plant growth and development, and promote soil microbe interactions. Carlactone, a common precursor to strigolactones, is produced by conserved enzymes found in a number of diverse species. Versions of the MORE AXILLARY GROWTH1 (MAX1) cytochrome P450 from rice and Arabidopsis thaliana make specific subsets of strigolactones from carlactone. However, the diversity of natural strigolactones suggests that additional enzymes are involved and remain to be discovered. Here, we use an innovative method that has revealed a missing enzyme involved in strigolactone metabolism. By using a transcriptomics approach involving a range of treatments that modify strigolactone biosynthesis gene expression coupled with reverse genetics, we identified LATERAL BRANCHING OXIDOREDUCTASE (LBO), a gene encoding an oxidoreductase-like enzyme of the 2-oxoglutarate and Fe(II)-dependent dioxygenase superfamily. Arabidopsis lbo mutants exhibited increased shoot branching, but the lbo mutation did not enhance the max mutant phenotype. Grafting indicated that LBO is required for a graft-transmissible signal that, in turn, requires a product of MAX1. Mutant lbo backgrounds showed reduced responses to carlactone, the substrate of MAX1, and methyl carlactonoate (MeCLA), a product downstream of MAX1. Furthermore, lbo mutants contained increased amounts of these compounds, and the LBO protein specifically converts MeCLA to an unidentified strigolactone-like compound. Thus, LBO function may be important in the later steps of strigolactone biosynthesis to inhibit shoot branching in Arabidopsis and other seed plants.
authors.affiliation: School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia;
authors.forename: Philip B
authors.identifier: 0000-0003-4871-9260
authors.initials: PB
authors.lastname: Brewer
authors.affiliation: Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya 321-8505, Japan;
authors.forename: Kaori
authors.initials: K
authors.lastname: Yoneyama
authors.affiliation: School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; Department of Agriculture and Fisheries, Ecosciences Precinct, Brisbane, QLD 4001, Australia;
authors.forename: Fiona
authors.initials: F
authors.lastname: Filardo
authors.affiliation: School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia;
authors.forename: Emma
authors.initials: E
authors.lastname: Meyers
authors.affiliation: School of Chemistry and Biochemistry, The University of Western Australia, Crawley, WA 6009, Australia;
authors.forename: Adrian
authors.initials: A
authors.lastname: Scaffidi
authors.affiliation: Research School of Biological Sciences, The Australian National University, Canberra, ACT 2601, Australia;
authors.forename: Tancred
authors.initials: T
authors.lastname: Frickey
authors.affiliation: Department of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka 599-8531, Japan;
authors.forename: Kohki
authors.initials: K
authors.lastname: Akiyama
authors.affiliation: Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan;
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Seto
authors.affiliation: School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia;
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Dun
authors.affiliation: School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; Department of Agriculture and Fisheries, Ecosciences Precinct, Brisbane, QLD 4001, Australia;
authors.forename: Julia E
authors.initials: JE
authors.lastname: Cremer
authors.affiliation: School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia;
authors.forename: Stephanie C
authors.initials: SC
authors.lastname: Kerr
authors.affiliation: School of Chemistry and Biochemistry, The University of Western Australia, Crawley, WA 6009, Australia; Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, WA 6009, Australia;
authors.forename: Mark T
authors.initials: MT
authors.lastname: Waters
authors.affiliation: School of Chemistry and Biochemistry, The University of Western Australia, Crawley, WA 6009, Australia;
authors.forename: Gavin R
authors.initials: GR
authors.lastname: Flematti
authors.affiliation: School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia;
authors.forename: Michael G
authors.initials: MG
authors.lastname: Mason
authors.affiliation: Research School of Biological Sciences, The Australian National University, Canberra, ACT 2601, Australia;
authors.forename: Georg
authors.initials: G
authors.lastname: Weiller
authors.affiliation: Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan;
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Yamaguchi
authors.affiliation: Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya 321-8505, Japan;
authors.forename: Takahito
authors.initials: T
authors.lastname: Nomura
authors.affiliation: School of Biological Sciences, University of Tasmania, Hobart, TAS 7001, Australia; Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Smith
authors.affiliation: Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya 321-8505, Japan;
authors.forename: Koichi
authors.initials: K
authors.lastname: Yoneyama
authors.affiliation: School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; c.beveridge@uq.edu.au.
authors.forename: Christine A
authors.initials: CA
authors.lastname: Beveridge
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D049308:Dioxygenases / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007501:Iron / Q000378:metabolism; D007656:Ketoglutaric Acids / Q000378:metabolism; D007783:Lactones / Q000378:metabolism*; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000378:metabolism*; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D059467:Transcriptome
chemical_list: D029681:Arabidopsis Proteins; D007656:Ketoglutaric Acids; D007783:Lactones; C470445:MAX1 protein, Arabidopsis; D010937:Plant Growth Regulators; C483518:strigol; D007501:Iron; D010088:Oxidoreductases; D049308:Dioxygenases
keywords: Arabidopsis; biosynthesis; branching; plant; strigolactone