Components of Arabidopsis defense- and ethylene-signaling pathways regulate susceptibility to Cauliflower mosaic virus by restricting long-distance movement

Mol Plant Microbe Interact. 2007 Jun;20(6):659-70. doi: 10.1094/MPMI-20-6-0659.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antimycin A / pharmacology
  • Arabidopsis / drug effects
  • Arabidopsis / genetics
  • Arabidopsis / immunology*
  • Arabidopsis / virology*
  • Biological Transport / drug effects
  • Caulimovirus / drug effects
  • Caulimovirus / physiology*
  • Ethylenes / metabolism*
  • Mitochondrial Proteins
  • Mutation / genetics
  • Oxidoreductases / metabolism
  • Plant Diseases / virology
  • Plant Proteins
  • Plants, Genetically Modified
  • Recombinant Fusion Proteins / metabolism
  • Salicylamides / pharmacology
  • Salicylic Acid / pharmacology
  • Signal Transduction* / drug effects
  • Time Factors
  • Virus Replication / drug effects


  • Ethylenes
  • Mitochondrial Proteins
  • Plant Proteins
  • Recombinant Fusion Proteins
  • Salicylamides
  • Antimycin A
  • salicylhydroxamic acid
  • ethylene
  • Oxidoreductases
  • alternative oxidase
  • Salicylic Acid