title: Non-indolyl cruciferous phytoalexins: Nasturlexins and tridentatols, a striking convergent evolution of defenses in terrestrial plants and marine animals?
abstract: Highly specialized chemical defense pathways are a particularly noteworthy metabolic characteristic of sessile organisms, whether terrestrial or marine, providing protection against pests and diseases. For this reason, knowledge of the metabolites involved in these processes is crucial to producing ecologically fit crops. Toward this end, the elicited chemical defenses of the crucifer watercress (Nasturtium officinale R. Br.), i.e. phytoalexins, were investigated and are reported. Almost three decades after publication of cruciferous phytoalexins derived from (S)-Trp, phytoalexins derived from other aromatic amino acids were isolated; their chemical structures were determined by analyses of their spectroscopic data and confirmed by synthesis. Nasturlexin A, nasturlexin B, and tridentatol C are hitherto unknown phenyl containing cruciferous phytoalexins produced by watercress under abiotic stress; tridentatol C is also produced by a marine animal (Tridentata marginata), where it functions in chemical defense against predators. The biosynthesis of these metabolites in both a terrestrial plant and a marine animal suggests a convergent evolution of unique metabolic pathways recruited for defense.
authors.affiliation: Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada. Electronic address: s.pedras@usask.ca.
authors.forename: M Soledade C
authors.initials: MS
authors.lastname: Pedras
authors.affiliation: Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada.
authors.forename: Q Huy
authors.initials: QH
authors.lastname: To
mesh_terms: D000818:Animals; D019607:Brassicaceae / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D008386:Marine Biology; D015394:Molecular Structure; D031223:Nasturtium / Q000502:physiology*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010636:Phenols; D012639:Seeds / Q000737:chemistry; D012717:Sesquiterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D014364:Tryptophan / Q000737:chemistry; D000094162:Phytoalexins
chemical_list: D010636:Phenols; D012717:Sesquiterpenes; D014364:Tryptophan; D000094162:Phytoalexins
keywords: Alternaria brassicicola; Brassicaceae; Brassinin; Crucifer; Gluconasturtiin; Leptosphaeria maculans; Nasturlexin; Nasturtium officinale; Phytoalexin; Sclerotinia sclerotiorum; Tridentata marginata