Lilium floral fragrance: A biochemical and genetic resource for aroma and flavor. (February 2016) - Johnson, Timothy S.
Abstract : Graphical abstract: Floral volatile characterization of five Lilium cultivars reveals specific and diverse chemical profiles, which uncovers a simple platform to perform comparative transcriptomics for volatile biosynthesis gene discovery. Highlights: High resolution volatile profiles for five Lilium cultivars were attained. PCA and hierarchical cluster analysis reveal specific and diverse chemical profiles. Gene cloning and transcriptional analysis reveal sequence conservation with dicots. 66 quantified volatile compounds reveals large metabolic diversity across cultivars. Proposed organism for studying complex volatile metabolism for numerous pathways. Abstract: Hybrid Lilium (common name lily) cultivars are among the top produced domestic fresh cut flowers and potted plants in the US today. Many hybrid Lilium cultivars produce large and showy flowers that emit copious amounts of volatile molecules, which can negatively affect a consumer's appreciation or limit use of the plant product. There are few publications focused on the biochemistry, genetics, and/or molecular regulation of floral volatile biosynthesis for Lilium cultivars. In an initial pursuit to provide breeders with molecular markers for floral volatile biosynthesis, a total of five commercially available oriental and oriental-trumpet hybrid Lilium cultivars were selected for analytical characterization of floral volatile emission. In total, 66 volatile molecules were qualified and quantitated among all cultivars. Chemical classes of identified volatiles include monoterpene hydrocarbons, monoterpene alcohols and aldehydes, phenylpropanoids, benzenoids, fatty-acid-derived, nitrogen-containing, and amino-acid-derived compounds. In general, the floral volatile profiles of the three oriental-trumpet hybrids were dominated by monoterpene hydrocarbons, monoterpene alcohols and aldehydes, while the two oriental hybrids were dominated by monoterpene alcohols and aldehydes and phenylpropanoids, respectively. Tepal tissues (two petal whirls) emitted the vast majority of total volatile molecules compared to the reproductive organs of the flowers. Tepal volatile profiles were cultivar specific with a high degree of distinction, which indicates the five cultivars chosen will provide an excellent differential genetic environment for gene discovery through comparative transcriptomics in the future. Cloning and assaying transcript accumulation from four floral volatile biosynthetic candidates provided few immediate or obvious trends with floral volatile emission.