title: 2'-epi-orobanchol and solanacol, two unique strigolactones, germination stimulants for root parasitic weeds, produced by tobacco.
abstract: Germination stimulants for root holoparasitic weeds broomrapes ( Orobanche and Phelipanche spp.) produced by tobacco ( Nicotiana tabacum L.) were purified and characterized. The root exudates of tobacco contained at least five different stimulants, and LC-MS/MS analyses revealed that four of them were strigolactones; a tetradehydrostrigol isomer, a didehydrostrigol isomer, and two strigol isomers. The two isomers of strigol were identified as (+)-orobanchol and its 2'-epimer by comparison of NMR and GC- and LC-MS data with those of synthetic standards. The structure of the tetradehydrostrigol isomer, the major stimulant of the bright yellow tobacco cultivars, was determined as 4-alpha-hydroxy-5,8-dimethyl-GR24 [( E)-4-alpha-hydroxy-5,8-dimethyl-3-(4-methyl-5-oxo-2,5-dihydrofuran-2-yloxy)methylene)-3a,4-dihydro-3 H-indeno[1,2- b]furan-2(8b H)-one] and named solanacol. 2'-Epi-orobanchol and solanacol are the first natural strigolactones having a 2'-epi stereochemistry and a benzene ring, respectively.
authors.affiliation: United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Xie
authors.forename: Dai
authors.initials: D
authors.lastname: Kusumoto
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: Kaori
authors.initials: K
authors.lastname: Yoneyama
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Yamada
authors.forename: Koichi
authors.initials: K
authors.lastname: Yoneyama
mesh_terms: D002853:Chromatography, Liquid; D018525:Germination / Q000187:drug effects*; D007783:Lactones / Q000032:analysis* / Q000737:chemistry / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D031672:Orobanche / Q000254:growth & development*; D018517:Plant Roots / Q000737:chemistry; D014026:Nicotiana / Q000737:chemistry*