title: Mild Potassium Chloride Stress Alters the Mineral Composition, Hormone Network, and Phenolic Profile in Artichoke Leaves.
abstract: There is a growing interest among consumers and researchers in the globe artichoke [Cynara cardunculus L. subsp. scolymus (L.) Hegi] leaf extract due to its nutraceutical and therapeutic properties. The application of an abiotic stress such as salinity can activate the stress-signaling pathways, thus enhancing the content of valuable phytochemicals. The aim of this study was to assess the metabolic changes in artichokes by probing the leaf metabolome of artichoke plants grown in a floating system and exposed to a relatively mild (30 mM) potassium chloride (KCl) salt stress. Potassium chloride treatment decreased the leaf dry biomass of artichoke, macro- and microelements in leaves (e.g., Ca, Mg, Mn, Zn, and B) but increased the concentrations of K and Cl. Metabolomics highlighted that the hormonal network of artichokes was strongly imbalanced by KCl. The indole-3-acetic acid conjugates, the brassinosteroids hormone 6-deoxocastasterone, and even more the cytokinin precursor N(6)-(Delta-2-isopentenyl)-adenosine-5'-triphosphate, strongly increased in leaves of KCl-treated plants. Moreover, KCl saline treatment induced accumulation of GA4, a bioactive form additional to the already known GA3. Another specific response to salinity was changes in the phenolic compounds profile, with flavones and isoflavones being decreased by KCl treatment, whereas flavonoid glycosides increased. The osmotic/oxidative stress that salinity generates also induced some expected changes at the biochemical level (e.g., ascorbate degradation, membrane lipid peroxidation, and accumulation of mannitol phosphate). These latter results help explain the molecular/physiological mechanisms that the plant uses to cope with potassium chloride stress exposure.
authors.affiliation: Institute of Environmental and Agricultural Chemistry, Università Cattolica del Sacro Cuore, Piacenza Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Lucini
authors.affiliation: Department of Agricultural and Forestry Sciences, University of Tuscia, Viterbo Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Borgognone
authors.affiliation: Department of Agricultural Sciences, University of Naples Federico II, Naples Italy.
authors.forename: Youssef
authors.initials: Y
authors.lastname: Rouphael
authors.affiliation: Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria, Centro di Ricerca per lo Studio delle Relazioni tra Pianta e Suolo, Roma Italy.
authors.forename: Mariateresa
authors.initials: M
authors.lastname: Cardarelli
authors.affiliation: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Piacenza Italy.
authors.forename: Jamila
authors.initials: J
authors.lastname: Bernardi
authors.affiliation: Department of Agricultural and Forestry Sciences, University of Tuscia, Viterbo Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Colla
keywords: Cynara cardunculus subsp. scolymus; flavonoid conjugates; lipid peroxidation; metabolomics; phytohormones; salinity