title: The Arabidopsis thaliana natriuretic peptide AtPNP-A is a systemic regulator of leaf dark respiration and signals via the phloem.
abstract: Plant natriuretic peptides (PNPs) belong to a novel class of peptidic signaling molecules that share some structural similarity to the N-terminal domain of expansins and affect physiological processes such as water and ion homeostasis at nano-molar concentrations. Here we show that a recombinant Arabidopsis thaliana PNP (AtPNP-A) rapidly increased the rate of dark respiration in treated leaves after 5 min. In addition, we observed increases in lower leaves, and with a lag time of 10 min, the effect spread to the upper leaves and subsequently (after 15 min) to the opposite leaves. This response signature is indicative of phloem mobility of the signal, a hypothesis that was further strengthened by the fact that cold girdling, which affects phloem but not xylem or apoplastic processes, delayed the long distance AtPNP-A effect. We conclude that locally applied AtPNP-A can induce a phloem-mobile signal that rapidly modifies plant homeostasis in distal parts.
authors.affiliation: Department of Biotechnology, University of the Western Cape, Bellville 7535, South Africa.
authors.forename: Oziniel
authors.initials: O
authors.lastname: Ruzvidzo
authors.forename: Lara
authors.initials: L
authors.lastname: Donaldson
authors.forename: Alex
authors.initials: A
authors.lastname: Valentine
authors.forename: Chris
authors.initials: C
authors.lastname: Gehring
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D019069:Cell Respiration / Q000235:genetics; D003080:Cold Temperature; D003624:Darkness; D004305:Dose-Response Relationship, Drug; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006706:Homeostasis; D045265:Natriuretic Peptides / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D052585:Phloem / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D015398:Signal Transduction; D013019:South Africa; D013997:Time Factors; D014867:Water / Q000378:metabolism; D052584:Xylem / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D045265:Natriuretic Peptides; C464762:PNP-A protein, Arabidopsis; D011994:Recombinant Proteins; D014867:Water