title: Signal signature of aboveground-induced resistance upon belowground herbivory in maize.
abstract: Plants activate local and systemic defence mechanisms upon exposure to stress. This innate immune response is partially regulated by plant hormones, and involves the accumulation of defensive metabolites. Although local defence reactions to herbivores are well studied, less is known about the impact of root herbivory on shoot defence. Here, we examined the effects of belowground infestation by the western corn rootworm Diabrotica virgifera virgifera on aboveground resistance in maize. Belowground herbivory by D. v. virgifera induced aboveground resistance against the generalist herbivore Spodoptera littoralis, and the necrotrophic pathogen Setosphaeria turcica. Furthermore, D. v. virgifera increased shoot levels of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), and primed the induction of chlorogenic acid upon subsequent infestation by S. littoralis. To gain insight into the signalling network behind this below- and aboveground defence interaction, we compiled a set of 32 defence-related genes, which can be used as transcriptional marker systems to detect activities of different hormone-response pathways. Belowground attack by D. v. virgifera triggered an ABA-inducible transcription pattern in the shoot. The quantification of defence hormones showed a local increase in the production of oxylipins after root and shoot infestation by D. v. virgifera and S. littoralis, respectively. On the other hand, ABA accumulated locally and systemically upon belowground attack by D. v. virgifera. Furthermore, D. v. virgifera reduced the aboveground water content, whereas the removal of similar quantities of root biomass had no effect. Our study shows that root herbivory by D. v. virgifera specifically alters the aboveground defence status of a maize, and suggests that ABA plays a role in the signalling network mediating this interaction.
authors.affiliation: Laboratory for Fundamental and Applied Research in Chemical Ecology (FARCE), University of Neuchâtel, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Erb
authors.forename: Victor
authors.initials: V
authors.lastname: Flors
authors.forename: Danielle
authors.initials: D
authors.lastname: Karlen
authors.forename: Elvira
authors.initials: E
authors.lastname: de Lange
authors.forename: Chantal
authors.initials: C
authors.lastname: Planchamp
authors.forename: Marco
authors.initials: M
authors.lastname: D'Alessandro
authors.forename: Ted C J
authors.initials: TC
authors.lastname: Turlings
authors.forename: Jurriaan
authors.initials: J
authors.lastname: Ton
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000818:Animals; D001203:Ascomycota / Q000502:physiology; D048588:Benzoxazines / Q000378:metabolism*; D002726:Chlorogenic Acid / Q000378:metabolism; D001517:Coleoptera / Q000502:physiology*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D007814:Larva / Q000502:physiology; D009036:Moths / Q000502:physiology; D054883:Oxylipins / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D018749:RNA, Plant / Q000378:metabolism; D015398:Signal Transduction; D003313:Zea mays / Q000235:genetics / Q000378:metabolism* / Q000502:physiology
chemical_list: D048588:Benzoxazines; D054883:Oxylipins; D010937:Plant Growth Regulators; D018749:RNA, Plant; D002726:Chlorogenic Acid; D000040:Abscisic Acid; C050733:2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one