title: Components of Arabidopsis defense- and ethylene-signaling pathways regulate susceptibility to Cauliflower mosaic virus by restricting long-distance movement.
abstract: We analyzed the susceptibility of Arabidopsis mutants with defects in salicylic acid (SA) and jasmonic acid (JA)/ethylene (ET) signaling to infection by Cauliflower mosaic virus (CaMV). Mutants cpr1-1 and cpr5-2, in which SA-dependent defense signaling is activated constitutively, were substantially more resistant than the wild type to systemic infection, implicating SA signaling in defense against CaMV. However, SA-deficient NahG, sid2-2, eds5-1, and pad4-1 did not show enhanced susceptibility. A cpr5 eds5 double mutant also was resistant, suggesting that resistance in cpr5 may function partially independently of SA. Treatment of cpr5 and cpr5 eds5, but not cpr1, with salicyl-hydroxamic acid, an inhibitor of alternative oxidase, partially restored susceptibility to wild-type levels. Mutants etr1-1, etr1-3, and ein2-1, and two mutants with lesions in ET/JA-mediated defense, eds4 and eds8, also showed reduced virus susceptibility, demonstrating that ET-dependent responses also play a role in susceptibility. We used a green fluorescent protein (GFP)-expressing CaMV recombinant to monitor virus movement. In mutants with reduced susceptibility, cpr1-1, cpr5-2, and etr1-1, CaMV-GFP formed local lesions similar to the wild type, but systemic spread was almost completely absent in cpr1 and cpr5 and was substantially reduced in etr1-1. Thus, mutations with enhanced systemic acquired resistance or compromised ET signaling show diminished long-distance virus movement.
authors.affiliation: Plant Science Group, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Love
authors.forename: Valérie
authors.initials: V
authors.lastname: Laval
authors.forename: Chiara
authors.initials: C
authors.lastname: Geri
authors.forename: Janet
authors.initials: J
authors.lastname: Laird
authors.forename: A Deri
authors.initials: AD
authors.lastname: Tomos
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hooks
authors.forename: Joel J
authors.initials: JJ
authors.lastname: Milner
mesh_terms: D000968:Antimycin A / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000276:immunology* / Q000821:virology*; D001692:Biological Transport / Q000187:drug effects; D017796:Caulimovirus / Q000187:drug effects / Q000502:physiology*; D005030:Ethylenes / Q000378:metabolism*; D024101:Mitochondrial Proteins; D009154:Mutation / Q000235:genetics; D010088:Oxidoreductases / Q000378:metabolism; D010935:Plant Diseases / Q000821:virology; D010940:Plant Proteins; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012457:Salicylamides / Q000494:pharmacology; D020156:Salicylic Acid / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014779:Virus Replication / Q000187:drug effects; D000099188:Alternative Oxidase
chemical_list: D000968:Antimycin A; D005030:Ethylenes; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D012457:Salicylamides; D020156:Salicylic Acid; D000099188:Alternative Oxidase; C005703:salicylhydroxamic acid; C036216:ethylene