title: Abscisic acid signals reorientation of polyamine metabolism to orchestrate stress responses via the polyamine exodus pathway in grapevine.
abstract: Polyamines (PAs) have been suggested to be implicated in plant responses to abiotic and biotic stress. Grapevine is a model perennial plant species whose cultivars respond differently to osmotic stress. In this study, we used two cultivars, one sensitive (S) and one tolerant (T) to drought. In adult vines subjected to drought under greenhouse conditions, total PAs were significantly lower in the control T- and higher in the control S-genotype and significantly increased or decreased, respectively, post-treatment. Soluble Put and Spd exhibited the greatest increase on d 8 post-treatment in the T- but not in the S-genotype, which accumulated soluble Spm. Abscisic acid (ABA) was differentially accumulated in T- and S-genotypes under drought conditions, and activated the PA biosynthetic pathway, which in turn was correlated with the differential increases in PA titers. In parallel, polyamine oxidases (PAOs) increased primarily in the S-genotype. ABA at least partially induced PA accumulation and exodus into the apoplast, where they were oxidized by the apoplastic amine oxidases (AOs), producing H2O2, which signaled secondary stress responses. The results here show that the ABA signaling pathway integrates PAs and AOs to regulate the generation of H2O2, which signals further stress responses or the PCD syndrome.
authors.affiliation: Department of Biology, University of Crete, P.O. Box 2280, 71409 Heraklion Crete, Greece.
authors.forename: Imene
authors.initials: I
authors.lastname: Toumi
authors.forename: Panagiotis N
authors.initials: PN
authors.lastname: Moschou
authors.forename: Konstantinos A
authors.initials: KA
authors.lastname: Paschalidis
authors.forename: Badra
authors.initials: B
authors.lastname: Bouamama
authors.forename: Asma
authors.initials: A
authors.lastname: Ben Salem-Fnayou
authors.forename: Abdel Wahed
authors.initials: AW
authors.lastname: Ghorbel
authors.forename: Ahmed
authors.initials: A
authors.lastname: Mliki
authors.forename: Kalliopi A
authors.initials: KA
authors.lastname: Roubelakis-Angelakis
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D055864:Droughts; D005838:Genotype; D006706:Homeostasis; D006861:Hydrogen Peroxide / Q000378:metabolism; D010084:Oxidation-Reduction; D011073:Polyamines / Q000378:metabolism*; D013312:Stress, Physiological; D027843:Vitis / Q000235:genetics / Q000378:metabolism*; D014867:Water / Q000378:metabolism
chemical_list: D011073:Polyamines; D014867:Water; D000040:Abscisic Acid; D006861:Hydrogen Peroxide