title: Identification and Characterization of the Iridoid Synthase Involved in Oleuropein Biosynthesis in Olive (Olea europaea) Fruits.
abstract: The secoiridoids are the main class of specialized metabolites present in olive (Olea europaea L.) fruit. In particular, the secoiridoid oleuropein strongly influences olive oil quality because of its bitterness, which is a desirable trait. In addition, oleuropein possesses a wide range of pharmacological properties, including antioxidant, anti-inflammatory, and anti-cancer activities. In accordance, obtaining high oleuropein varieties is a main goal of molecular breeding programs. Here we use a transcriptomic approach to identify candidate genes belonging to the secoiridoid pathway in olive. From these candidates, we have functionally characterized the olive homologue of iridoid synthase (OeISY), an unusual terpene cyclase that couples an NAD (P)H-dependent 1,4-reduction step with a subsequent cyclization, and we provide evidence that OeISY likely generates the monoterpene scaffold of oleuropein in olive fruits. OeISY, the first pathway gene characterized for this type of secoiridoid, is a potential target for breeding programs in a high value secoiridoid-accumulating species.
authors.affiliation: From the Departments of Metabolic Biology and; the Institute of Biosciences and Bio-resources, National Research Council (CNR), 06128 Perugia, Italy,. Electronic address: fiammetta.alagna@crea.gov.it.
authors.forename: Fiammetta
authors.initials: F
authors.lastname: Alagna
authors.affiliation: the Copenhagen Plant Science Centre & Section for Plant Biochemistry, Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark, and.
authors.forename: Fernando
authors.initials: F
authors.lastname: Geu-Flores
authors.affiliation: Biological Chemistry, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Hajo
authors.initials: H
authors.lastname: Kries
authors.affiliation: the ENEA Trisaia Research Center, 75026 Rotondella, Matera, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Panara
authors.affiliation: the Institute of Biosciences and Bio-resources, National Research Council (CNR), 06128 Perugia, Italy.
authors.forename: Luciana
authors.initials: L
authors.lastname: Baldoni
authors.affiliation: Biological Chemistry, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: O'Connor
authors.affiliation: From the Departments of Metabolic Biology and.
authors.forename: Anne
authors.initials: A
authors.lastname: Osbourn
mesh_terms: D000595:Amino Acid Sequence; D053898:Biosynthetic Pathways; D018360:Crystallography, X-Ray; D005638:Fruit / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D057888:Iridoid Glucosides; D039823:Iridoids / Q000378:metabolism*; D008025:Ligases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D031658:Olea / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D059467:Transcriptome
chemical_list: D057888:Iridoid Glucosides; D039823:Iridoids; D010940:Plant Proteins; C002769:oleuropein; D010088:Oxidoreductases; D008025:Ligases
keywords: Oleaceae; biosynthesis; enzyme; monoterpenes; phenolic compounds; plant; secoiridoids; secondary metabolism; transcriptomics