Resistance to Botrytis cinerea Induced in Arabidopsis by Elicitors Is Independent of Salicylic Acid, Ethylene, or Jasmonate Signaling But Requires PHYTOALEXIN DEFICIENT3  

Abstract

Oligogalacturonides (OGs) released from plant cell walls by pathogen polygalacturonases induce a variety of host defense responses. Here we show that in Arabidopsis (Arabidopsis thaliana), OGs increase resistance to the necrotrophic fungal pathogen Botrytis cinerea independently of jasmonate (JA)-, salicylic acid (SA)-, and ethylene (ET)-mediated signaling. Microarray analysis showed that about 50% of the genes regulated by OGs, including genes encoding enzymes involved in secondary metabolism, show a similar change of expression during B. cinerea infection. In particular, expression of PHYTOALEXIN DEFICIENT3 (PAD3) is strongly up-regulated by both OGs and infection independently of SA, JA, and ET. OG treatments do not enhance resistance to B. cinerea in the pad3 mutant or in underinducer after pathogen and stress1, a mutant with severely impaired PAD3 expression in response to OGs. Similarly to OGs, the bacterial flagellin peptide elicitor flg22 also enhanced resistance to B. cinerea in a PAD3-dependent manner, independently of SA, JA, and ET. This work suggests, therefore, that elicitors released from the cell wall during pathogen infection contribute to basal resistance against fungal pathogens through a signaling pathway also activated by pathogen-associated molecular pattern molecules.

Expansive Phenotypic Landscape of Botrytis cinerea Shows Differential Contribution of Genetic Diversity and Plasticity

“…The remaining defense compounds showed a similar pattern, with the exception of the proportion of 4MOI3M to the total indole glucosinolates and camalexin, which both showed a large and significant proportion of variance explained by the B. cinerea genotype (h 2 = 0.45 and 0.37, respectively). Intriguingly, 4MOI3M and camalexin are the host defense compounds most frequently associated with pathogen defense in Arabidopsis (Ferrari et al 2003(Ferrari et al , 2007Kliebenstein et al 2005). Thus, identifying the loci in the B. cinerea genome that differentially stimulate these defense compounds could provide information about the interaction of host and pathogen.…”

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

“…Elicitors represent an attractive potential alternative to fungicides since they can induce plant defense responses [3]. Numerous elicitors of different nature have been previously described to protect plants against B. cinerea, such as rhamnolipids (RLs) [33], oligogalacturonides (OGs) [33,34], chitosan [35] and its quaternized oligomers (QCOS) [35,36], a heat-stable protein PebC1 [37] and ceratoplatanin (CP) [38]. In this work we characterized the protective effect of the novel elicitor AsES against B. cinerea.…”

The Arabidopsis NUCLEUS- AND PHRAGMOPLAST-LOCALIZED KINASE1-Related Protein Kinases Are Required for Elicitor-Induced Oxidative Burst and Immunity

“…It is known that the expression of PHYTOALEXIN DEFICIENT3 (PAD3), encoding the cytochrome CYP71B15 that catalyzes the last step of camalexin biosynthesis, is required for OG-induced protection against B. cinerea (Ferrari et al, 2007). We therefore analyzed whether elicitor-induced expression of PAD3 is affected in the anp single mutants.…”

“…To assess whether the altered regulation of defense gene expression affects the response of anp mutants to pathogens, we examined susceptibility to B. cinerea as well as the protection response induced by OG (Ferrari et al, 2007) and elf18 against this fungus. Adult single and double mutant plants as well as wild-type (Col-0 and Ws) plants were sprayed with OGs, elf18, or water, and excised leaves were infected with B. cinerea after 24 h. All mutants exhibited a basal susceptibility to the fungus similar to that of the wild type, with the exception of the anp2 anp3 double mutant, which was more resistant, likely due to the basal up-regulation of stress-related genes (Fig.…”

“…Protection assays against B. cinerea were performed as previously described (Ferrari et al, 2007) with slight modifications. Four-week-old intact rosettes were sprayed with water, OGs (200 mg mL -1 ), or elf18 (1 mM), and after 24 h, fully expanded leaves were detached and placed in petri dishes containing 0.8% (w/v) plant agar, with the petiole embedded in the medium.…”