title: Ozone-induced responses in Croton floribundus Spreng. (Euphorbiaceae): metabolic cross-talk between volatile organic compounds and calcium oxalate crystal formation.
abstract: Here, we proposed that volatile organic compounds (VOC), specifically methyl salicylate (MeSA), mediate the formation of calcium oxalate crystals (COC) in the defence against ozone (O3) oxidative damage. We performed experiments using Croton floribundus, a pioneer tree species that is tolerant to O3 and widely distributed in the Brazilian forest. This species constitutively produces COC. We exposed plants to a controlled fumigation experiment and assessed biochemical, physiological, and morphological parameters. O3 induced a significant increase in the concentrations of constitutive oxygenated compounds, MeSA and terpenoids as well as in COC number. Our analysis supported the hypothesis that ozone-induced VOC (mainly MeSA) regulate ROS formation in a way that promotes the opening of calcium channels and the subsequent formation of COC in a fast and stable manner to stop the consequences of the reactive oxygen species in the tissue, indeed immobilising the excess calcium (caused by acute exposition to O3) that can be dangerous to the plant. To test this hypothesis, we performed an independent experiment spraying MeSA over C. floribundus plants and observed an increase in the number of COC, indicating that this compound has a potential to directly induce their formation. Thus, the tolerance of C. floribundus to O3 oxidative stress could be a consequence of a higher capacity for the production of VOC and COC rather than the modulation of antioxidant balance. We also present some insights into constitutive morphological features that may be related to the tolerance that this species exhibits to O3.
authors.affiliation: Programa de Pós-Graduação em Biodiversidade Vegetal e Meio Ambiente, Instituto de Botânica, São Paulo, São Paulo, Brazil.
authors.forename: Poliana
authors.initials: P
authors.lastname: Cardoso-Gustavson
authors.affiliation: Núcleo de Pesquisa em Ecologia, Instituto de Botânica, São Paulo, São Paulo, Brazil.
authors.forename: Vanessa Palermo
authors.initials: VP
authors.lastname: Bolsoni
authors.affiliation: Núcleo de Pesquisa em Ecologia, Instituto de Botânica, São Paulo, São Paulo, Brazil.
authors.forename: Debora Pinheiro
authors.initials: DP
authors.lastname: de Oliveira
authors.affiliation: Núcleo de Pesquisa em Ecologia, Instituto de Botânica, São Paulo, São Paulo, Brazil.
authors.forename: Maria Tereza Gromboni
authors.initials: MT
authors.lastname: Guaratini
authors.affiliation: Núcleo de Pesquisa em Fisiologia e Bioquímica, Instituto de Botânica, São Paulo, São Paulo, Brazil.
authors.forename: Marcos Pereira Marinho
authors.initials: MP
authors.lastname: Aidar
authors.affiliation: Núcleo de Pesquisa em Fisiologia e Bioquímica, Instituto de Botânica, São Paulo, São Paulo, Brazil.
authors.forename: Mauro Alexandre
authors.initials: MA
authors.lastname: Marabesi
authors.affiliation: Núcleo de Pesquisa em Anatomia, Instituto de Botânica, São Paulo, São Paulo, Brazil.
authors.forename: Edenise Segala
authors.initials: ES
authors.lastname: Alves
authors.affiliation: Núcleo de Pesquisa em Ecologia, Instituto de Botânica, São Paulo, São Paulo, Brazil.
authors.forename: Silvia Ribeiro
authors.initials: SR
authors.lastname: de Souza
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002129:Calcium Oxalate / Q000378:metabolism*; D019069:Cell Respiration / Q000187:drug effects*; D029802:Croton / Q000187:drug effects / Q000378:metabolism*; D010083:Oxidants, Photochemical / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010126:Ozone / Q000494:pharmacology*; D055549:Volatile Organic Compounds / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D010083:Oxidants, Photochemical; D055549:Volatile Organic Compounds; D002129:Calcium Oxalate; D010126:Ozone; D002118:Calcium