title: Rice cytochrome P450 MAX1 homologs catalyze distinct steps in strigolactone biosynthesis.
abstract: Strigolactones (SLs) are a class of phytohormones and rhizosphere signaling compounds with high structural diversity. Three enzymes, carotenoid isomerase DWARF27 and carotenoid cleavage dioxygenases CCD7 and CCD8, were previously shown to convert all-trans-β-carotene to carlactone (CL), the SL precursor. However, how CL is metabolized to SLs has remained elusive. Here, by reconstituting the SL biosynthetic pathway in Nicotiana benthamiana, we show that a rice homolog of Arabidopsis More Axillary Growth 1 (MAX1), encodes a cytochrome P450 CYP711 subfamily member that acts as a CL oxidase to stereoselectively convert CL into ent-2'-epi-5-deoxystrigol (B-C lactone ring formation), the presumed precursor of rice SLs. A protein encoded by a second rice MAX1 homolog then catalyzes the conversion of ent-2'-epi-5-deoxystrigol to orobanchol. We therefore report that two members of CYP711 enzymes can catalyze two distinct steps in SL biosynthesis, identifying the first enzymes involved in B-C ring closure and a subsequent structural diversification step of SLs.
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands.
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Applied Bioinformatics, Plant Research International, Wageningen, the Netherlands.
authors.forename: Aalt D J
authors.initials: AD
authors.lastname: van Dijk
authors.affiliation: School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Australia.
authors.forename: Adrian
authors.initials: A
authors.lastname: Scaffidi
authors.affiliation: School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Australia.
authors.forename: Gavin R
authors.initials: GR
authors.lastname: Flematti
authors.affiliation: Faculty of Biology, University of Freiburg, Freiburg, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Hofmann
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands.
authors.forename: Tatsiana
authors.initials: T
authors.lastname: Charnikhova
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands.
authors.forename: Francel
authors.initials: F
authors.lastname: Verstappen
authors.affiliation: Department of Biology, University of York, Heslington, York, UK.
authors.forename: Jo
authors.initials: J
authors.lastname: Hepworth
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands.
authors.forename: Sander
authors.initials: S
authors.lastname: van der Krol
authors.affiliation: 1] Department of Biology, University of York, Heslington, York, UK. [2] Sainsbury Laboratory, University of Cambridge, Cambridge, UK.
authors.forename: Ottoline
authors.initials: O
authors.lastname: Leyser
authors.affiliation: School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Australia.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Smith
authors.affiliation: Radboud University Nijmegen, Institute for Molecules and Materials, Cluster of Organic Chemistry, Nijmegen, the Netherlands.
authors.forename: Binne
authors.initials: B
authors.lastname: Zwanenburg
authors.affiliation: 1] Center for Desert Agriculture, BESE Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia. [2] Faculty of Biology, University of Freiburg, Freiburg, Germany.
authors.forename: Salim
authors.initials: S
authors.lastname: Al-Babili
authors.affiliation: 1] Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands. [2] Bioscience, Plant Research International, Wageningen, the Netherlands.
authors.forename: Carolien
authors.initials: C
authors.lastname: Ruyter-Spira
authors.affiliation: 1] Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands. [2] Centre for Biosystems Genomics, Wageningen, the Netherlands.
authors.forename: Harro J
authors.initials: HJ
authors.lastname: Bouwmeester
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D055162:Biocatalysis; D049308:Dioxygenases / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007783:Lactones / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D012275:Oryza / Q000201:enzymology* / Q000235:genetics; D010937:Plant Growth Regulators / Q000096:biosynthesis*; D030821:Plants, Genetically Modified; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics; D019207:beta Carotene / Q000378:metabolism
chemical_list: C528323:5-deoxystrigol; D029681:Arabidopsis Proteins; C575857:D27 protein, Arabidopsis; D007783:Lactones; C470445:MAX1 protein, Arabidopsis; D010937:Plant Growth Regulators; C571055:carlactone; C472678:orobanchol; D019207:beta Carotene; C494441:CCD7 protein, Arabidopsis; C494442:CCD8 protein, Arabidopsis; D049308:Dioxygenases