title: Volatiles produced by soil-borne endophytic bacteria increase plant pathogen resistance and affect tritrophic interactions.
abstract: Volatile organic compounds (VOCs) released by soil microorganisms influence plant growth and pathogen resistance. Yet, very little is known about their influence on herbivores and higher trophic levels. We studied the origin and role of a major bacterial VOC, 2,3-butanediol (2,3-BD), on plant growth, pathogen and herbivore resistance, and the attraction of natural enemies in maize. One of the major contributors to 2,3-BD in the headspace of soil-grown maize seedlings was identified as Enterobacter aerogenes, an endophytic bacterium that colonizes the plants. The production of 2,3-BD by E. aerogenes rendered maize plants more resistant against the Northern corn leaf blight fungus Setosphaeria turcica. On the contrary, E. aerogenes-inoculated plants were less resistant against the caterpillar Spodoptera littoralis. The effect of 2,3-BD on the attraction of the parasitoid Cotesia marginiventris was more variable: 2,3-BD application to the headspace of the plants had no effect on the parasitoids, but application to the soil increased parasitoid attraction. Furthermore, inoculation of seeds with E. aerogenes decreased plant attractiveness, whereas inoculation of soil with a total extract of soil microbes increased parasitoid attraction, suggesting that the effect of 2,3-BD on the parasitoid is indirect and depends on the composition of the microbial community.
authors.affiliation: Laboratory for Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
authors.forename: Marco
authors.initials: M
authors.lastname: D'Alessandro
authors.affiliation: Laboratory for Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.|Root-Herbivore Interactions Group, Max Planck Institute for Chemical Ecology, Jena, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Erb
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.
authors.forename: Jurriaan
authors.initials: J
authors.lastname: Ton
authors.affiliation: Laboratory for Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
authors.forename: Anna
authors.initials: A
authors.lastname: Brandenburg
authors.affiliation: Laboratory for Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
authors.forename: Danielle
authors.initials: D
authors.lastname: Karlen
authors.affiliation: Laboratory of Microbiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
authors.forename: Jakob
authors.initials: J
authors.lastname: Zopfi
authors.affiliation: Laboratory for Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
authors.forename: Ted C J
authors.initials: TCJ
authors.lastname: Turlings
mesh_terms: D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D002072:Butylene Glycols / Q000378:metabolism; D015169:Colony Count, Microbial; D060467:Disease Resistance; D017753:Ecosystem; D060026:Endophytes / Q000378:metabolism*; D021902:Enterobacter aerogenes / Q000254:growth & development; D008401:Gas Chromatography-Mass Spectrometry; D060434:Herbivory; D054884:Host-Pathogen Interactions / Q000276:immunology; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology / Q000469:parasitology; D036226:Seedlings / Q000382:microbiology; D012988:Soil Microbiology; D018411:Spodoptera / Q000502:physiology; D055549:Volatile Organic Compounds / Q000378:metabolism*; D014835:Volatilization; D003313:Zea mays / Q000254:growth & development / Q000382:microbiology* / Q000469:parasitology
chemical_list: D002072:Butylene Glycols; D055549:Volatile Organic Compounds; C026978:2,3-butylene glycol
keywords: 2; 3-butanediol; acetoin; induced systemic resistance; maize; volatile organic compounds