title: Interplay between JA, SA and ABA signalling during basal and induced resistance against Pseudomonas syringae and Alternaria brassicicola.
abstract: We have examined the role of the callose synthase PMR4 in basal resistance and beta-aminobutyric acid-induced resistance (BABA-IR) of Arabidopsis thaliana against the hemi-biotrophic pathogen Pseudomonas syringae and the necrotrophic pathogen Alternaria brassicicola. Compared to wild-type plants, the pmr4-1 mutant displayed enhanced basal resistance against P. syringae, which correlated with constitutive expression of the PR-1 gene. Treating the pmr4-1 mutant with BABA boosted the already elevated levels of PR-1 gene expression, and further increased the level of resistance. Hence, BABA-IR against P. syringae does not require PMR4-derived callose. Conversely, pmr4-1 plants showed enhanced susceptibility to A. brassicicola, and failed to show BABA-IR. Wild-type plants showing BABA-IR against A. brassicicola produced increased levels of JA. The pmr4-1 mutant produced less JA upon A. brassicicola infection than the wild-type. Blocking SA accumulation in pmr4-1 restored basal resistance, but not BABA-IR against A. brassicicola. This suggests that the mutant's enhanced susceptibility to A. brassicicola is caused by SA-mediated suppression of JA, whereas the lack of BABA-IR is caused by its inability to produce callose. A. brassicicola infection suppressed ABA accumulation. Pre-treatment with BABA antagonized this ABA accumulation, and concurrently potentiated expression of the ABA-responsive ABI1 gene. Hence, BABA prevents pathogen-induced suppression of ABA accumulation, and sensitizes the tissue to ABA, causing augmented deposition of PMR4-derived callose.
authors: Laboratory of Molecular and Cellular Biology, Institute of Botany, University of Neuchâtel, Rue Emile-Argand 11, Case Postale 158, 2009 Neuchâtel, Switzerland.
authors: Victor
authors: V
authors: Flors
authors: Jurriaan
authors: J
authors: Ton
authors: Ronald
authors: R
authors: van Doorn
authors: Gabor
authors: G
authors: Jakab
authors: Pilar
authors: P
authors: García-Agustín
authors: Brigitte
authors: B
authors: Mauch-Mani
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D000528:Alternaria / Q000502:physiology*; D000613:Aminobutyrates / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D005936:Glucans / Q000378:metabolism; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D054884:Host-Pathogen Interactions; D009154:Mutation; D054883:Oxylipins / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology*; D044224:Pseudomonas syringae / Q000502:physiology*; D020156:Salicylic Acid / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D000613:Aminobutyrates; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D005936:Glucans; D054883:Oxylipins; C047667:3-aminobutyric acid; C011006:jasmonic acid; D000040:Abscisic Acid; C048306:callose; D005964:Glucosyltransferases; C020570:1,3-beta-glucan synthase; D020156:Salicylic Acid