title: Volatile emissions of scented Alstroemeria genotypes are dominated by terpenes, and a myrcene synthase gene is highly expressed in scented Alstroemeria flowers.
abstract: Native to South America, Alstroemeria flowers are known for their colourful tepals, and Alstroemeria hybrids are an important cut flower. However, in common with many commercial cut flowers, virtually all the commercial Alstroemeria hybrids are not scented. The cultivar 'Sweet Laura' is one of very few scented commercial Alstroemeria hybrids. Characterization of the volatile emission profile of these cut flowers revealed three major terpene compounds: (E)-caryophyllene, humulene (also known as α-caryophyllene), an ocimene-like compound, and several minor peaks, one of which was identified as myrcene. The profile is completely different from that of the parental scented species A. caryophyllaea. Volatile emission peaked at anthesis in both scented genotypes, coincident in cv. 'Sweet Laura' with the maximal expression of a putative terpene synthase gene AlstroTPS. This gene was preferentially expressed in floral tissues of both cv. 'Sweet Laura' and A. caryophyllaea. Characterization of the AlstroTPS gene structure from cv. 'Sweet Laura' placed it as a member of the class III terpene synthases, and the predicted 567 amino acid sequence placed it into the subfamily TPS-b. The conserved sequences R(28)(R)X(8)W and D(321)DXXD are the putative Mg(2+)-binding sites, and in vitro assay of AlstroTPS expressed in Escherichia coli revealed that the encoded enzyme possesses myrcene synthase activity, consistent with a role for AlstroTPS in scent production in Alstroemeria cv. 'Sweet Laura' flowers.
authors.affiliation: School of Biosciences, Cardiff University, Cardiff CF10 3TL, UK.
authors.forename: Danilo
authors.initials: D
authors.lastname: Aros
authors.forename: Veronica
authors.initials: V
authors.lastname: Gonzalez
authors.forename: Rudolf K
authors.initials: RK
authors.lastname: Allemann
authors.forename: Carsten T
authors.initials: CT
authors.lastname: Müller
authors.forename: Carlo
authors.initials: C
authors.lastname: Rosati
authors.forename: Hilary J
authors.initials: HJ
authors.lastname: Rogers
mesh_terms: D000080462:Acyclic Monoterpenes; D000475:Alkenes / Q000737:chemistry / Q000378:metabolism; D019883:Alkyl and Aryl Transferases / Q000235:genetics / Q000378:metabolism*; D031402:Alstroemeria / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D035264:Flowers / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D019753:Intramolecular Lyases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D039821:Monoterpenes / Q000737:chemistry / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D013729:Terpenes / Q000737:chemistry / Q000378:metabolism*; D014835:Volatilization
chemical_list: D000080462:Acyclic Monoterpenes; D000475:Alkenes; D039821:Monoterpenes; D010940:Plant Proteins; D013729:Terpenes; C509595:myrcene; D019883:Alkyl and Aryl Transferases; C108877:terpene synthase; D019753:Intramolecular Lyases