title: A Metabolic Gene Cluster in the Wheat W1 and the Barley Cer-cqu Loci Determines β-Diketone Biosynthesis and Glaucousness.
abstract: The glaucous appearance of wheat (Triticum aestivum) and barley (Hordeum vulgare) plants, that is the light bluish-gray look of flag leaf, stem, and spike surfaces, results from deposition of cuticular β-diketone wax on their surfaces; this phenotype is associated with high yield, especially under drought conditions. Despite extensive genetic and biochemical characterization, the molecular genetic basis underlying the biosynthesis of β-diketones remains unclear. Here, we discovered that the wheat W1 locus contains a metabolic gene cluster mediating β-diketone biosynthesis. The cluster comprises genes encoding proteins of several families including type-III polyketide synthases, hydrolases, and cytochrome P450s related to known fatty acid hydroxylases. The cluster region was identified in both genetic and physical maps of glaucous and glossy tetraploid wheat, demonstrating entirely different haplotypes in these accessions. Complementary evidence obtained through gene silencing in planta and heterologous expression in bacteria supports a model for a β-diketone biosynthesis pathway involving members of these three protein families. Mutations in homologous genes were identified in the barley eceriferum mutants defective in β-diketone biosynthesis, demonstrating a gene cluster also in the β-diketone biosynthesis Cer-cqu locus in barley. Hence, our findings open new opportunities to breed major cereal crops for surface features that impact yield and stress response.
authors.affiliation: Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Shelly
authors.identifier: 0000-0002-9949-3743
authors.initials: S
authors.lastname: Hen-Avivi
authors.affiliation: Faculty of Life Sciences, Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Orna
authors.identifier: 0000-0003-3655-3611
authors.initials: O
authors.lastname: Savin
authors.affiliation: Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: Radu C
authors.identifier: 0000-0002-6396-9869
authors.initials: RC
authors.lastname: Racovita
authors.affiliation: Plant Biology and Crop Science Department, Rothamsted Research, Harpenden AL5 2JQ, United Kingdom.
authors.forename: Wing-Sham
authors.initials: WS
authors.lastname: Lee
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom.
authors.forename: Nikolai M
authors.identifier: 0000-0003-1329-5138
authors.initials: NM
authors.lastname: Adamski
authors.affiliation: Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Sergey
authors.initials: S
authors.lastname: Malitsky
authors.affiliation: Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Efrat
authors.initials: E
authors.lastname: Almekias-Siegl
authors.affiliation: Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Matan
authors.initials: M
authors.lastname: Levy
authors.affiliation: INRA-Centre National de Ressources Génomiques Végétales, F-31326 Castanet Tolosan, France.
authors.forename: Sonia
authors.identifier: 0000-0003-4446-1426
authors.initials: S
authors.lastname: Vautrin
authors.affiliation: INRA-Centre National de Ressources Génomiques Végétales, F-31326 Castanet Tolosan, France.
authors.forename: Hélène
authors.identifier: 0000-0002-5492-1062
authors.initials: H
authors.lastname: Bergès
authors.affiliation: The Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Gilgi
authors.identifier: 0000-0001-8513-1998
authors.initials: G
authors.lastname: Friedlander
authors.affiliation: Electron Microscopy Unit, Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Elena
authors.identifier: 0000-0001-5517-8429
authors.initials: E
authors.lastname: Kartvelishvily
authors.affiliation: NRGene, 7403648 Ness Ziona, Israel.
authors.forename: Gil
authors.initials: G
authors.lastname: Ben-Zvi
authors.affiliation: Department of Postharvest Science of Fresh Produce, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel.
authors.forename: Noam
authors.initials: N
authors.lastname: Alkan
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom.
authors.forename: Cristobal
authors.initials: C
authors.lastname: Uauy
authors.affiliation: Plant Biology and Crop Science Department, Rothamsted Research, Harpenden AL5 2JQ, United Kingdom.
authors.forename: Kostya
authors.identifier: 0000-0001-6324-4123
authors.initials: K
authors.lastname: Kanyuka
authors.affiliation: Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada Department of Botany, The University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Jetter
authors.affiliation: Faculty of Life Sciences, Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel asaph.aharoni@weizmann.ac.il adistel@post.tau.ac.il.
authors.forename: Assaf
authors.identifier: 0000-0003-1777-3053
authors.initials: A
authors.lastname: Distelfeld
authors.affiliation: Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel asaph.aharoni@weizmann.ac.il adistel@post.tau.ac.il.
authors.forename: Asaph
authors.identifier: 0000-0002-6077-1590
authors.initials: A
authors.lastname: Aharoni
mesh_terms: D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D020868:Gene Silencing / Q000502:physiology; D001467:Hordeum / Q000235:genetics* / Q000378:metabolism*; D007659:Ketones / Q000737:chemistry / Q000378:metabolism*; D005810:Multigene Family / Q000235:genetics* / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D057891:Tetraploidy; D014908:Triticum / Q000235:genetics* / Q000378:metabolism*
chemical_list: D007659:Ketones; D010940:Plant Proteins