title: Isolation and identification of an allelopathic phenylethylamine in rice.
abstract: Allelopathy is the process whereby an organic chemical (allelochemical) released from one plant influences the growth and development of other plants. Allelochemicals produced by specific rice (Oryza sativa L.) cultivars have potential to manage barnyard grass (Echinochloa crus-galli L.), a major yield-limiting weed species in rice production systems in Asia and North America. In this study, isolation and identification of an allelopathic compound, N-trans-cinnamoyltyramine (NTCT), in a Vietnamese rice cultivar 'OM 5930' was accomplished through bioassay-guided purification using reversed-phase liquid chromatography coupled with spectroscopic techniques, including tandem mass spectrometry, high resolution mass spectrometry, as well as one-dimensional and two-dimensional (1)H NMR and (13)C NMR spectroscopy. The identified compound, NTCT is considered a β-phenylethylamine. NTCT inhibited root and hypocotyl growth of cress (Lepidium sativum L.), barnyard grass and red sprangletop (Leptochloa chinensis L. Nees) at concentrations as low as 0.24 μM. The ED50 (concentration required for 50% inhibition) of NTCT on barnyard grass root and hypocotyl elongation were 1.35 and 1.85 μM, respectively. Results further demonstrated that mortality of barnyard grass and red sprangletop seedlings was >80% at a concentration of 2.4 μM of NTCT. By 20 days after transplanting, 0.425 nmol of NTCT per OM 5930 rice seedling was released into the culture solution. With concentrations of 42 μg g(-1) fresh weight, production of NTCT in intact rice plants can be considered high. These findings suggest that developing plants of Vietnamese rice cultivar OM 5930 release NTCT and may be utilized to suppress barnyard grass in rice fields. The potency of NTCT may encourage development of this compound as a bio-herbicide.
authors.affiliation: Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Ho
authors.initials: H
authors.lastname: Le Thi
authors.affiliation: School of Natural Resources, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Chung-Ho
authors.initials: CH
authors.lastname: Lin
authors.affiliation: Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Reid J
authors.initials: RJ
authors.lastname: Smeda
authors.affiliation: Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Leigh
authors.affiliation: Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Wei G
authors.initials: WG
authors.lastname: Wycoff
authors.affiliation: Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA. Electronic address: fritschif@missouri.edu.
authors.forename: Felix B
authors.initials: FB
authors.lastname: Fritschi
mesh_terms: D002934:Cinnamates / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology*; D006540:Herbicides / Q000494:pharmacology; D015394:Molecular Structure; D012275:Oryza / Q000737:chemistry* / Q000502:physiology; D010627:Phenethylamines / Q000032:analysis / Q000302:isolation & purification*; D010675:Pheromones / Q000494:pharmacology*; D013237:Stereoisomerism; D014439:Tyramine / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology; D000094162:Phytoalexins
chemical_list: D002934:Cinnamates; D006540:Herbicides; D010627:Phenethylamines; D010675:Pheromones; D014439:Tyramine; C479307:N-cinnamoyltyramine; D000094162:Phytoalexins; C029261:phenethylamine
keywords: Allelopathy; Barnyard grass; Brassicaceae; Cress; Echinochloa crus-galli; Lepidium sativum L.; Leptochloa chinensis (L.) Nees; N-trans-cinnamoyltyramine; Oryza sativa L. cv. OM 5930; Poaceae; Red sprangletop; Rice; allelochemicals; phenylethylamine