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Targeting novel chemical and constitutive primed metabolites against P lectosphaerella cucumerina
Author(s) -
Gamir Jordi,
Pastor Victoria,
Kaever Alexander,
Cerezo Miguel,
Flors Victor
Publication year - 2014
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12465
Subject(s) - biology , mutant , biochemistry , priming (agriculture) , arabidopsis thaliana , plant defense against herbivory , indole test , amino acid , microbiology and biotechnology , botany , gene , germination
Summary Priming is a physiological state for protection of plants against a broad range of pathogens, and is achieved through stimulation of the plant immune system. Various stimuli, such as beneficial microbes and chemical induction, activate defense priming. In the present study, we demonstrate that impairment of the high‐affinity nitrate transporter 2.1 (encoded by NRT 2.1 ) enables A rabidopsis to respond more quickly and strongly to P lectosphaerella cucumerina attack, leading to enhanced resistance. The A rabidopsis thaliana mutant lin1 (affected in NRT 2.1 ) is a priming mutant that displays constitutive resistance to this necrotroph, with no associated developmental or growth costs. Chemically induced priming by β–aminobutyric acid treatment, the constitutive priming mutant ocp3 and the constitutive priming present in the lin1 mutant result in a common metabolic profile within the same plant–pathogen interactions. The defense priming significantly affects sugar metabolism, cell‐wall remodeling and shikimic acid derivatives levels, and results in specific changes in the amino acid profile and three specific branches of Trp metabolism, particularly accumulation of indole acetic acid, indole‐3–carboxaldehyde and camalexin, but not the indolic glucosinolates. Metabolomic analysis facilitated identification of three metabolites in the priming fingerprint: galacturonic acid, indole‐3–carboxylic acid and hypoxanthine. Treatment of plants with the latter two metabolites by soil drenching induced resistance against P . cucumerina , demonstrating that these compounds are key components of defense priming against this necrotrophic fungus. Here we demonstrate that indole‐3–carboxylic acid induces resistance by promoting papillae deposition and H 2 O 2 production, and that this is independent of PR 1 , VSP 2 and PDF 1.2 priming.