title: Shifts in plant foliar and floral metabolomes in response to the suppression of the associated microbiota.
abstract: BACKGROUND
  The phyllospheric microbiota is assumed to play a key role in the metabolism of host plants. Its role in determining the epiphytic and internal plant metabolome, however, remains to be investigated. We analyzed the Liquid Chromatography-Mass Spectrometry (LC-MS) profiles of the epiphytic and internal metabolomes of the leaves and flowers of Sambucus nigra with and without external antibiotic treatment application.
  
  
  RESULTS
  The epiphytic metabolism showed a degree of complexity similar to that of the plant organs. The suppression of microbial communities by topical applications of antibiotics had a greater impact on the epiphytic metabolome than on the internal metabolomes of the plant organs, although even the latter changed significantly both in leaves and flowers. The application of antibiotics decreased the concentration of lactate in both epiphytic and organ metabolomes, and the concentrations of citraconic acid, acetyl-CoA, isoleucine, and several secondary compounds such as terpenes and phenols in the epiphytic extracts. The metabolite pyrogallol appeared in the floral epiphytic community only after the treatment. The concentrations of the amino acid precursors of the ketoglutarate-synthesis pathway tended to decrease in the leaves and to increase in the foliar epiphytic extracts.
  
  
  CONCLUSIONS
  These results suggest that anaerobic and/or facultative anaerobic bacteria were present in high numbers in the phyllosphere and in the apoplasts of S. nigra. The results also show that microbial communities play a significant role in the metabolomes of plant organs and could have more complex and frequent mutualistic, saprophytic, and/or parasitic relationships with internal plant metabolism than currently assumed.
authors.affiliation: CSIC, Global Ecology Unit CREAF- CSIC-UAB, Cerdanyola del Vallès, Catalonia, 08193, Spain. albert.gargallo@gmail.com.|CREAF, Cerdanyola del Vallès, Catalonia, 08193, Spain. albert.gargallo@gmail.com.|Service of Nuclear Magnetic Resonance, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Catalonia, 08913, Spain. albert.gargallo@gmail.com.
authors.forename: Albert
authors.initials: A
authors.lastname: Gargallo-Garriga
authors.affiliation: CSIC, Global Ecology Unit CREAF- CSIC-UAB, Cerdanyola del Vallès, Catalonia, 08193, Spain.|CREAF, Cerdanyola del Vallès, Catalonia, 08193, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Sardans
authors.affiliation: Service of Nuclear Magnetic Resonance, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Catalonia, 08913, Spain.
authors.forename: Míriam
authors.initials: M
authors.lastname: Pérez-Trujillo
authors.affiliation: Pacific Northwest National Laboratory, Richland, WA, 99354, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Guenther
authors.affiliation: CSIC, Global Ecology Unit CREAF- CSIC-UAB, Cerdanyola del Vallès, Catalonia, 08193, Spain.|CREAF, Cerdanyola del Vallès, Catalonia, 08193, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Llusià
authors.affiliation: CSIC, Global Ecology Unit CREAF- CSIC-UAB, Cerdanyola del Vallès, Catalonia, 08193, Spain.|CREAF, Cerdanyola del Vallès, Catalonia, 08193, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Rico
authors.affiliation: CREAF, Cerdanyola del Vallès, Catalonia, 08193, Spain.|Department BABVE, Universitat Autònoma de Barcelona, Barcelona, Catalonia, 08913, Spain.
authors.forename: Jaume
authors.initials: J
authors.lastname: Terradas
authors.affiliation: CSIC, Global Ecology Unit CREAF- CSIC-UAB, Cerdanyola del Vallès, Catalonia, 08193, Spain.|CREAF, Cerdanyola del Vallès, Catalonia, 08193, Spain.
authors.forename: Gerard
authors.initials: G
authors.lastname: Farré-Armengol
authors.affiliation: CSIC, Global Ecology Unit CREAF- CSIC-UAB, Cerdanyola del Vallès, Catalonia, 08193, Spain.|CREAF, Cerdanyola del Vallès, Catalonia, 08193, Spain.
authors.forename: Iolanda
authors.initials: I
authors.lastname: Filella
authors.affiliation: Service of Nuclear Magnetic Resonance, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Catalonia, 08913, Spain.
authors.forename: Teodor
authors.initials: T
authors.lastname: Parella
authors.affiliation: CSIC, Global Ecology Unit CREAF- CSIC-UAB, Cerdanyola del Vallès, Catalonia, 08193, Spain.|CREAF, Cerdanyola del Vallès, Catalonia, 08193, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Peñuelas
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D002701:Chloramphenicol / Q000494:pharmacology; D002853:Chromatography, Liquid; D035264:Flowers / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology; D054884:Host-Pathogen Interactions / Q000187:drug effects; D013058:Mass Spectrometry; D055442:Metabolome / Q000187:drug effects / Q000502:physiology*; D055432:Metabolomics / Q000379:methods; D064307:Microbiota / Q000187:drug effects / Q000502:physiology*; D015999:Multivariate Analysis; D010118:Oxytetracycline / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology; D025341:Principal Component Analysis; D027924:Sambucus nigra / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology; D013307:Streptomycin / Q000494:pharmacology; D013559:Symbiosis / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D002701:Chloramphenicol; D010118:Oxytetracycline; D013307:Streptomycin
keywords: Epiphytic and endophytic microbiota; Sambucus nigra; antibiotics; metabolites