title: Germination stimulants of Phelipanche ramosa in the rhizosphere of Brassica napus are derived from the glucosinolate pathway.
abstract: Phelipanche ramosa is a major parasitic weed of Brassica napus. The first step in a host-parasitic plant interaction is stimulation of parasite seed germination by compounds released from host roots. However, germination stimulants produced by B. napus have not been identified yet. In this study, we characterized the germination stimulants that accumulate in B. napus roots and are released into the rhizosphere. Eight glucosinolate-breakdown products were identified and quantified in B. napus roots by gas chromatography-mass spectrometry. Two (3-phenylpropanenitrile and 2-phenylethyl isothiocyanate [2-PEITC]) were identified in the B. napus rhizosphere. Among glucosinolate-breakdown products, P. ramosa germination was strongly and specifically triggered by isothiocyanates, indicating that 2-PEITC, in particular, plays a key role in the B. napus-P. ramosa interaction. Known strigolactones were not detected by ultraperformance liquid chromatography-tandem mass spectrometry, and seed of Phelipanche and Orobanche spp. that respond to strigolactones but not to isothiocyanates did not germinate in the rhizosphere of B. napus. Furthermore, both wild-type and strigolactone biosynthesis mutants of Arabidopsis thaliana Atccd7 and Atccd8 induced similar levels of P. ramosa seed germination, suggesting that compounds other than strigolactone function as germination stimulants for P. ramosa in other Brassicaceae spp. Our results open perspectives on the high adaptation potential of root-parasitic plants under host-driven selection pressures.
authors.forename: Bathilde
authors.initials: B
authors.lastname: Auger
authors.forename: Jean-Bernard
authors.initials: JB
authors.lastname: Pouvreau
authors.forename: Karinne
authors.initials: K
authors.lastname: Pouponneau
authors.forename: Kaori
authors.initials: K
authors.lastname: Yoneyama
authors.forename: Grégory
authors.initials: G
authors.lastname: Montiel
authors.forename: Bruno
authors.initials: B
authors.lastname: Le Bizec
authors.forename: Koichi
authors.initials: K
authors.lastname: Yoneyama
authors.forename: Philippe
authors.initials: P
authors.lastname: Delavault
authors.forename: Régine
authors.initials: R
authors.lastname: Delourme
authors.forename: Philippe
authors.initials: P
authors.lastname: Simier
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000469:parasitology; D029681:Arabidopsis Proteins / Q000235:genetics; D029688:Brassica napus / Q000737:chemistry / Q000469:parasitology*; D049308:Dioxygenases / Q000235:genetics; D008401:Gas Chromatography-Mass Spectrometry; D018525:Germination / Q000187:drug effects; D005961:Glucosinolates / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D006790:Host-Parasite Interactions / Q000187:drug effects*; D017879:Isothiocyanates / Q000494:pharmacology; D007783:Lactones / Q000494:pharmacology; D009154:Mutation; D031670:Orobanchaceae / Q000187:drug effects* / Q000502:physiology; D053147:Plant Exudates / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry / Q000469:parasitology; D057685:Plant Weeds / Q000187:drug effects / Q000502:physiology; D058441:Rhizosphere; D012639:Seeds / Q000187:drug effects / Q000502:physiology; D013329:Structure-Activity Relationship
chemical_list: D029681:Arabidopsis Proteins; D005961:Glucosinolates; D017879:Isothiocyanates; D007783:Lactones; D053147:Plant Exudates; C037152:isothiocyanic acid; C494441:CCD7 protein, Arabidopsis; C494442:CCD8 protein, Arabidopsis; D049308:Dioxygenases