title: Identification of defense compounds in Barbarea vulgaris against the herbivore Phyllotreta nemorum by an ecometabolomic approach.
abstract: Winter cress (Barbarea vulgaris) is resistant to a range of insect species. Some B. vulgaris genotypes are resistant, whereas others are susceptible, to herbivory by flea beetle larvae (Phyllotreta nemorum). Metabolites involved in resistance to herbivory by flea beetles were identified using an ecometabolomic approach. An F2 population representing the whole range from full susceptibility to full resistance to flea beetle larvae was generated by a cross between a susceptible and a resistant B. vulgaris plant. This F2 offspring was evaluated with a bioassay measuring the ability of susceptible flea beetle larvae to survive on each plant. Metabolites that correlated negatively with larvae survival were identified through correlation, cluster, and principal component analyses. Two main clusters of metabolites that correlate negatively with larvae survival were identified. Principal component analysis grouped resistant and susceptible plants as well as correlated metabolites. Known saponins, such as hederagenin cellobioside and oleanolic acid cellobioside, as well as two other saponins correlated significantly with plant resistance. This study shows the potential of metabolomics to identify bioactive compounds involved in plant defense.
authors.affiliation: Center for Molecular Plant Physiology, Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
authors.forename: Vera
authors.initials: V
authors.lastname: Kuzina
authors.forename: Claus Thorn
authors.initials: CT
authors.lastname: Ekstrøm
authors.forename: Sven Bode
authors.initials: SB
authors.lastname: Andersen
authors.forename: Jens Kvist
authors.initials: JK
authors.lastname: Nielsen
authors.forename: Carl Erik
authors.initials: CE
authors.lastname: Olsen
authors.forename: Søren
authors.initials: S
authors.lastname: Bak
mesh_terms: D000818:Animals; D031216:Barbarea / Q000276:immunology* / Q000378:metabolism*; D002853:Chromatography, Liquid; D016000:Cluster Analysis; D001517:Coleoptera / Q000502:physiology*; D003433:Crosses, Genetic; D017753:Ecosystem; D005247:Feeding Behavior / Q000502:physiology*; D007814:Larva / Q000502:physiology; D013058:Mass Spectrometry; D055442:Metabolome; D055432:Metabolomics / Q000379:methods*; D009828:Oleanolic Acid / Q000031:analogs & derivatives / Q000032:analysis; D018515:Plant Leaves / Q000378:metabolism; D025341:Principal Component Analysis; D012503:Saponins / Q000378:metabolism; D016019:Survival Analysis
chemical_list: D012503:Saponins; D009828:Oleanolic Acid; C025763:hederagenin