title: Low levels of strigolactones in roots as a component of the systemic signal of drought stress in tomato.
abstract: Strigolactones (SL) contribute to drought acclimatization in shoots, because SL-depleted plants are hypersensitive to drought due to stomatal hyposensitivity to abscisic acid (ABA). However, under drought, SL biosynthesis is repressed in roots, suggesting organ specificity in their metabolism and role. Because SL can be transported acropetally, such a drop may also affect shoots, as a systemic indication of stress. We investigated this hypothesis by analysing molecularly and physiologically wild-type (WT) tomato (Solanum lycopersicum) scions grafted onto SL-depleted rootstocks, compared with self-grafted WT and SL-depleted genotypes, during a drought time-course. Shoots receiving few SL from the roots behaved as if under mild stress even if irrigated. Their stomata were hypersensitive to ABA (likely via a localized enhancement of SL synthesis in shoots). Exogenous SL also enhanced stomata sensitivity to ABA. As the partial shift of SL synthesis from roots to shoots mimics what happens under drought, a reduction of root-produced SL might represent a systemic signal unlinked from shootward ABA translocation, and sufficient to prime the plant for better stress avoidance.
authors.affiliation: Laboratory of Plant Physiology, DISAFA - Turin University, Grugliasco, 10095, TO, Italy.
authors.forename: Ivan
authors.initials: I
authors.lastname: Visentin
authors.affiliation: Laboratory of Plant Physiology, DISAFA - Turin University, Grugliasco, 10095, TO, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Vitali
authors.affiliation: Laboratory of Plant Physiology, DISAFA - Turin University, Grugliasco, 10095, TO, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Ferrero
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, 6708, PB Wageningen, the Netherlands.
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, 6708, PB Wageningen, the Netherlands.
authors.forename: Carolien
authors.initials: C
authors.lastname: Ruyter-Spira
authors.affiliation: Laboratory of Growth Regulators, Institute of Experimental Botany ASCR & Palacky University Olomouc, Olomouc, Czech Republic.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Novák
authors.affiliation: Laboratory of Growth Regulators, Institute of Experimental Botany ASCR & Palacky University Olomouc, Olomouc, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Strnad
authors.affiliation: Laboratory of Plant Physiology, DISAFA - Turin University, Grugliasco, 10095, TO, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Lovisolo
authors.affiliation: Laboratory of Plant Physiology, DISAFA - Turin University, Grugliasco, 10095, TO, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Schubert
authors.affiliation: Laboratory of Plant Physiology, DISAFA - Turin University, Grugliasco, 10095, TO, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Cardinale
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D053898:Biosynthetic Pathways / Q000235:genetics; D003681:Dehydration; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007783:Lactones / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000235:genetics / Q000502:physiology*; D008954:Models, Biological; D010641:Phenotype; D018515:Plant Leaves / Q000502:physiology; D018517:Plant Roots / Q000378:metabolism*; D018520:Plant Shoots / Q000235:genetics / Q000378:metabolism; D018526:Plant Transpiration; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological / Q000235:genetics; D014867:Water / Q000502:physiology
chemical_list: D007783:Lactones; D012333:RNA, Messenger; D014867:Water; D000040:Abscisic Acid
keywords: abscisic acid (ABA); drought; strigolactones (SL); systemic signalling; tomato (Solanum lycopersicum)