Wounding of Arabidopsis leaves causes a powerful but transient protection against Botrytis infection

Abstract

SummaryPhysical injury inflicted on living tissue makes it vulnerable to invasion by pathogens. Wounding of Arabidopsis thaliana leaves, however, does not conform to this concept and leads to immunity to Botrytis cinerea, the causal agent of grey mould. In wounded leaves, hyphal growth was strongly inhibited compared to unwounded controls. Wound-induced resistance was not associated with salicylic acid-, jasmonic acid-or ethylene-dependent defence responses. The phytoalexin camalexin was found to be involved in this defence response as camalexin-deficient mutants were not protected after wounding and the B. cinerea strains used here were sensitive to this compound. Wounding alone did not lead to camalexin production but primed its accumulation after inoculation with B. cinerea, further supporting the role of camalexin in wound-induced resistance. In parallel with increased camalexin production, genes involved in the biosynthesis of camalexin were induced faster in wounded and infected plants in comparison with unwounded and infected plants. Glutathione was also found to be required for resistance, as mutants deficient in c-glutamylcysteine synthetase showed susceptibility to B. cinerea after wounding, indicating that wild-type basal levels of glutathione are required for the wound-induced resistance. Furthermore, expression of the gene encoding glutathione-S-transferase 1 was primed by wounding in leaves inoculated with B. cinerea. In addition, the priming of MAP kinase activity was observed after inoculation of wounded leaves with B. cinerea compared to unwounded inoculated controls. Our results demonstrate how abiotic stress can induce immunity to virulent strains of B. cinerea, a process that involves camalexin and glutathione.

Complex Genetics Control Natural Variation inArabidopsis thalianaResistance toBotrytis cinerea

“…Additional molecular plant defense mechanisms for postinitiation lesion inhibition have not been explicitly described, but are believed to be largely regulated via jasmonate and ethylene signaling (Thomma et al 1998(Thomma et al , 1999Mengiste et al 2003;Thaler et al 2004). Recent work has described a strong effect of wound-induced defenses on spreading of B. cinerea lesions; these defenses include, but are not limited to, increased and more rapid camalexin accumulation (Chassot et al 2008). Characterizing molecular regulation of a known induced defense, camalexin, may shed light on broader mechanisms of defense against B. cinerea that could be applicable to plant species other than A. thaliana.…”

The novel elicitor AsES triggers a defense response against Botrytis cinerea in Arabidopsis thaliana

“…Briefly, a spore suspension of B. cinerea at a final concentration of 5×10 4 spores ml −1 and AsES (3,30,60,150 or 300 nM) were mixed to a final volume of 30 l. 10 l droplets were deposited on a slide and kept in high humid conditions inside dark hermetic boxes, placed in a growth chamber under the same conditions as for plant infections. Pictures were taken at 3, 6 and 24 h post incubation with a digital camera attached to a Leica DMR microscope with bright-field settings.…”

“…SA and camalexin were quantified as previously described [29] and [30] respectively. For each biological replicate, treated leaves from six plants (corresponding to about 200 mg fresh weight) were harvested, pooled and immediately frozen at −20 • C. The amount of SA and camalexin was expressed in ng mg −1 fresh weight (FW) and corrected with ortho-anisic acid as internal standard.…”

Quantitative Peptidomics Study Reveals That a Wound-Induced Peptide from PR-1 Regulates Immune Signaling in Tomato

“…Systemin was the first identified signaling peptide and also the first confirmed peptide elicitor of DAMPs in plants. It is expected that several signaling peptides are involved in combating herbivore and pathogen attack (Cheong et al, 2002;Francia et al, 2007;Chassot et al, 2008), but the details of the regulation of antiherbivore and antipathogen responses by peptides during wounding stress still await elucidation. Several DAMP peptides have been discovered in other plant species and suggested to be bioactive in tomato (Boller and Felix, 2009b;Campos et al, 2014); these include HypSys (Pearce et al, 2001a;Narvaez-Vasquez et al, 2007), RALF (Pearce et al, 2001b), and Pep1 (Huffaker et al, 2006;Trivilin et al, 2014).…”