title: Direct and individual analysis of stress-related phytohormone dispersion in the vascular system of Cucurbita maxima after flagellin 22 treatment.
abstract: • The stress-related phytohormones, salicylic acid (SA) and abscisic acid (ABA), and the three jasmonates, jasmonic acid (JA), cis-12-oxo-phytodienoic acid (cis-OPDA), and (+)-7-iso-jasmonoyl-L-isoleucine (JA-Ile), were investigated in phloem and xylem exudates of Cucurbita maxima. • Phloem and xylem exudates were separately collected and analysed via liquid chromatography-mass spectrometry. • We show direct evidence for all three jasmonates, ABA, and SA in both phloem and xylem exudates of C. maxima. JA and JA-Ile concentrations are higher in xylem (JA: c(xylem) ≈ 199.5 nM, c(phloem) ≈ 43.9 nM; JA-Ile: c(xylem) ≈ 7.9 nM, c(phloem) ≈ 1.6 nM), whereas ABA and SA concentrations are higher in phloem exudates (ABA: c(xylem) ≈ 37.1 nM, c(phloem) ≈ 142.6 nM; SA: c(xylem) ≈ 61.6 nM, c(phloem) ≈ 1319 nM). During bacteria-derived flagellin 22 (flg22)-triggered remote root-to-shoot signalling, phytohormone concentration changed rapidly both in phloem and xylem. • The unequal distribution of phytohormones suggests that phloem and xylem have distinct roles in defence responses. Our data shed light on systemic phytohormone signalling and help explain how plants cope with environmental challenges by lateral exchange between phloem and xylem. Our analysis is a starting point for further investigations of how phytohormones contribute to phloem- and xylem-based defence signalling.
authors.affiliation: Research Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology and Applied Zoology, Justus Liebig University, Heinrich-Buff-Ring 26-32, D-35392, Gießen, Germany.
authors.forename: Alexandra C U
authors.initials: ACU
authors.lastname: Furch
authors.affiliation: Institute for Botany, Justus Liebig University, Heinrich-Buff-Ring 38, D-35392, Gießen, Germany.
authors.forename: Matthias R
authors.initials: MR
authors.lastname: Zimmermann
authors.affiliation: Research Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology and Applied Zoology, Justus Liebig University, Heinrich-Buff-Ring 26-32, D-35392, Gießen, Germany.
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Kogel
authors.affiliation: Department of Biochemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745, Jena, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Reichelt
authors.affiliation: Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745, Jena, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Mithöfer
mesh_terms: D028464:Cucurbita / Q000187:drug effects / Q000502:physiology*; D005408:Flagellin / Q000494:pharmacology*; D052585:Phloem / Q000187:drug effects / Q000502:physiology; D053147:Plant Exudates / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology*; D058526:Plant Vascular Bundle / Q000187:drug effects / Q000502:physiology*; D013312:Stress, Physiological / Q000187:drug effects*; D052584:Xylem / Q000187:drug effects / Q000502:physiology
chemical_list: D053147:Plant Exudates; D010937:Plant Growth Regulators; D005408:Flagellin
keywords: abscisic acid; cucurbits; exudates; flg22; jasmonates; phloem/xylemphytohormones; plant defence; salicylic acid