title: Root ABA Accumulation in Long-Term Water-Stressed Plants is Sustained by Hormone Transport from Aerial Organs.
abstract: The reduced pool of the ABA precursors, β,β-carotenoids, in roots does not account for the substantial increase in ABA content in response to water stress (WS) conditions, suggesting that ABA could be transported from other organs. Basipetal transport was interrupted by stem-girdling, and ABA levels were determined in roots after two cycles of WS induced by transplanting plants to dry perlite. Leaf applications of isotope-labeled ABA and reciprocal grafting of ABA-deficient tomato mutants were used to confirm the involvement of aerial organs on root ABA accumulation. Disruption of basipetal transport reduced ABA accumulation in roots, and this decrease was more severe after two consecutive WS periods. This effect was linked to a sharp decrease in the β,β-carotenoid pool in roots in response to water deficit. Significant levels of isotope-labeled ABA were transported from leaves to roots, mainly in plants subjected to water dehydration. Furthermore, the use of different ABA-deficient tomato mutants in reciprocal grafting combinations with wild-type genotypes confirmed the involvement of aerial organs in the ABA accumulation in roots. In conclusion, accumulation of ABA in roots after long-term WS periods largely relies on the aerial organs, suggesting a reduced ability of the roots to synthesize ABA from carotenoids. Furthermore, plants are able to transport ABA basipetally to sustain high hormone levels in roots.
authors.affiliation: Ecofisiología y Biotecnología, Departamento de Ciències Agraries i del Medi Natural, Universitat Jaume I, E-12071 Castellón de la Plana, Spain.
authors.forename: Matías
authors.initials: M
authors.lastname: Manzi
authors.affiliation: Instituto Nacional de Investigación Agropecuaria (INIA), Salto, Uruguay Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain.
authors.forename: Joanna
authors.initials: J
authors.lastname: Lado
authors.affiliation: Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain.
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Rodrigo
authors.affiliation: Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Zacarías
authors.affiliation: Ecofisiología y Biotecnología, Departamento de Ciències Agraries i del Medi Natural, Universitat Jaume I, E-12071 Castellón de la Plana, Spain.
authors.forename: Vicent
authors.initials: V
authors.lastname: Arbona
authors.affiliation: Ecofisiología y Biotecnología, Departamento de Ciències Agraries i del Medi Natural, Universitat Jaume I, E-12071 Castellón de la Plana, Spain aurelio.gomez@uji.es.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Gómez-Cadenas
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D001692:Biological Transport; D053898:Biosynthetic Pathways; D002338:Carotenoids / Q000096:biosynthesis; D002957:Citrus / Q000378:metabolism*; D003681:Dehydration; D018551:Solanum lycopersicum / Q000378:metabolism*; D009928:Organ Specificity; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism*; D036226:Seedlings / Q000378:metabolism; D014867:Water / Q000378:metabolism
chemical_list: D010937:Plant Growth Regulators; D014867:Water; D002338:Carotenoids; D000040:Abscisic Acid
keywords: ABA-GE; Basipetal transport; Carotenoids; Drought; Girdling; Water deficit