title: Root-to-Shoot Hormonal Communication in Contrasting Rootstocks Suggests an Important Role for the Ethylene Precursor Aminocyclopropane-1-carboxylic Acid in Mediating Plant Growth under Low-Potassium Nutrition in Tomato.
abstract: Selection and breeding of rootstocks that can tolerate low K supply may increase crop productivity in low fertility soils and reduce fertilizer application. However, the underlying physiological traits are still largely unknown. In this study, 16 contrasting recombinant inbred lines (RILs) derived from a cross between domestic and wild tomato species (Solanum lycopersicum×Solanum pimpinellifolium) have been used to analyse traits related to the rootstock-mediated induction of low (L, low shoot fresh weight) or high (H, high shoot fresh weight) vigor to a commercial F1 hybrid grown under control (6 mM,c) and low-K (1 mM,k). Based on hormonal and ionomic composition in the root xylem sap and the leaf nutritional status after long-term (7 weeks) exposure low-K supply, a model can be proposed to explain the rootstocks effects on shoot performance with the ethylene precursor aminocyclopropane-1-carboxylic acid (ACC) playing a pivotal negative role. The concentration of this hormone was higher in the low-vigorLcandLkrootstocks under both conditions, increased in the sensitiveHcLkplants under low-K while it was reduced in the high-vigorHkones. Low ACC levels would promote the transport of Kvs. Na in the vigorousHkgrafted plants. Along with K, Ca, and S, micronutrient uptake and transport were also activated in the tolerantHkcombinations under low-K. Additionally, an interconversion oftrans-zeatin intotrans-zeatin riboside would contribute to decrease ACC in the tolerantLcHkplants. The high vigor induced by theHkplants can also be explained by an interaction of ACC with other hormones (cytokinins and salicylic, abscisic and jasmonic acids). Therefore,Hkrootstocks convert an elite tomato F1 cultivar into a (micro) nutrient-efficient phenotype, improving growth under reduced K fertilization.
authors.affiliation: Centro de Edafologia y Biologia Aplicada del Segura (CSIC) Murcia, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Martínez-Andújar
authors.affiliation: Centro de Edafologia y Biologia Aplicada del Segura (CSIC) Murcia, Spain.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Albacete
authors.affiliation: Centro de Edafologia y Biologia Aplicada del Segura (CSIC) Murcia, Spain.
authors.forename: Ascensión
authors.initials: A
authors.lastname: Martínez-Pérez
authors.affiliation: Instituto de Bioingeniería, Universidad Miguel Hernández, Edificio Vinalopó Alicante, Spain.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Pérez-Pérez
authors.affiliation: Instituto Valenciano de Investigaciones Agrarias (IVIA) Valencia, Spain.
authors.forename: María José
authors.initials: MJ
authors.lastname: Asins
authors.affiliation: Centro de Edafologia y Biologia Aplicada del Segura (CSIC) Murcia, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Pérez-Alfocea
keywords: Solanum; grafting; micronutrients; phytohormones; recombinant inbred lines; root-to-shoot communication