title: Role of dioxygenase α-DOX2 and SA in basal response and in hexanoic acid-induced resistance of tomato (Solanum lycopersicum) plants against Botrytis cinerea.
abstract: Resistance of tomato (Solanum Lycopersicum) to the fungal pathogen Botrytis cinerea requires complex interplay between hormonal signalling. In this study, we explored the involvement of new oxylipins in the tomato basal and induced response to this necrotroph through the functional analysis of the tomato α-dioxygenase2 (α-DOX2)-deficient mutant divaricata. We also investigated the role of SA in the defence response against this necrotrophic fungus using SA-deficient tomato nahG plants. The plants lacking dioxigenase α-DOX2, which catalyses oxylipins production from fatty acids, were more susceptible to Botrytis, and hexanoic acid-induced resistance (Hx-IR) was impaired; hence α-DOX2 is required for both tomato defence and the enhanced protection conferred by natural inducer hexanoic acid (Hx) against B. cinerea. The divaricata plants accumulated less pathogen-induced callose and presented lower levels of jasmonic acid (JA) and 12-oxo-phytodienoic acid (OPDA) upon infection if compared to the wild type. Glutathion-S-transferase (GST) gene expression decreased and ROS production significantly increased in Botrytis-infected divaricata plants. These results indicate that absence of α-DOX2 influences the hormonal changes, oxidative burst and callose deposition that occur upon Botrytis infection in tomato. The study of SA-deficient nahG tomato plants showed that the plants with low SA levels displayed increased resistance to Botrytis, but were unable to display Hx-IR. This supports the involvement of SA in Hx-IR. NaghG plants displayed reduced callose and ROS accumulation upon infection and an increased GST expression. This reflects a positive relationship between SA and these defensive mechanisms in tomato. Finally, Hx boosted the pathogen-induced callose in nahG plants, suggesting that this priming mechanism is SA-independent. Our results support the involvement of the oxylipins pathway and SA in tomato response to Botrytis, probably through complex crosstalk of the hormonal balance with callose and ROS accumulation, and reinforce the role of the oxidative stress in the outcome of the plant-Botrytis interaction.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Valencia, Instituto de Agroquímica y Tecnología de los Alimentos (IATA, CSIC), Avda. Agustín Escardino 7, 46980 Paterna, Valencia, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Angulo
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Valencia, Instituto de Agroquímica y Tecnología de los Alimentos (IATA, CSIC), Avda. Agustín Escardino 7, 46980 Paterna, Valencia, Spain; Departamento de Biología Experimental, Universidad de Jaén, Campus Las Lagunillas s/n, 23071 Jaén, Spain.
authors.forename: María
authors.initials: M
authors.lastname: de la O Leyva
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Valencia, Instituto de Agroquímica y Tecnología de los Alimentos (IATA, CSIC), Avda. Agustín Escardino 7, 46980 Paterna, Valencia, Spain.
authors.forename: Ivan
authors.initials: I
authors.lastname: Finiti
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Valencia, Instituto de Agroquímica y Tecnología de los Alimentos (IATA, CSIC), Avda. Agustín Escardino 7, 46980 Paterna, Valencia, Spain.
authors.forename: Jaime
authors.initials: J
authors.lastname: López-Cruz
authors.affiliation: Laboratorio de Bioquímica y Biotecnología. Área de Fisiología Vegetal, Departamento de Ciencias Agrarias y del Medio Natural, ESTCE, Universitat Jaume I, 12071 Castellón, Spain.
authors.forename: Emma
authors.initials: E
authors.lastname: Fernández-Crespo
authors.affiliation: Laboratorio de Bioquímica y Biotecnología. Área de Fisiología Vegetal, Departamento de Ciencias Agrarias y del Medio Natural, ESTCE, Universitat Jaume I, 12071 Castellón, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: García-Agustín
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Valencia, Instituto de Agroquímica y Tecnología de los Alimentos (IATA, CSIC), Avda. Agustín Escardino 7, 46980 Paterna, Valencia, Spain. Electronic address: carmen.gonzalez@uv.es.
authors.forename: Carmen
authors.initials: C
authors.lastname: González-Bosch
mesh_terms: D020171:Botrytis / Q000502:physiology*; D002208:Caproates / Q000494:pharmacology*; D003517:Cyclopentanes / Q000378:metabolism; D049308:Dioxygenases / Q000235:genetics / Q000378:metabolism*; D060467:Disease Resistance; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005936:Glucans / Q000378:metabolism; D018551:Solanum lycopersicum / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000276:immunology; D054883:Oxylipins / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism
chemical_list: D002208:Caproates; D003517:Cyclopentanes; D005231:Fatty Acids, Unsaturated; D005936:Glucans; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D017382:Reactive Oxygen Species; C037652:hexanoic acid; C025999:12-oxophytodienoic acid; C011006:jasmonic acid; C048306:callose; D049308:Dioxygenases; D020156:Salicylic Acid
keywords: Botrytis cinerea; Dioxygenase; Hexanoic acid; Salicylic acid; Solanum lycopersicum