title: Biological control of bacterial wilt in Arabidopsis thaliana involves abscissic acid signalling.
abstract: Means to control bacterial wilt caused by the phytopathogenic root bacteria Ralstonia solanacearum are limited. Mutants in a large cluster of genes (hrp) involved in the pathogenicity of R. solanacearum were successfully used in a previous study as endophytic biocontrol agents in challenge inoculation experiments on tomato. However, the molecular mechanisms controlling this resistance remained unknown. We developed a protection assay using Arabidopsis thaliana as a model plant and analyzed the events underlying the biological control by genetic, transcriptomic and molecular approaches. High protection rates associated with a significant decrease in the multiplication of R. solanacearum were observed in plants pre-inoculated with a ΔhrpB mutant strain. Neither salicylic acid, nor jasmonic acid/ethylene played a role in the establishment of this resistance. Microarray analysis showed that 26% of the up-regulated genes in protected plants are involved in the biosynthesis and signalling of abscissic acid (ABA). In addition 21% of these genes are constitutively expressed in the irregular xylem cellulose synthase mutants (irx), which present a high level of resistance to R. solanacearum. We propose that inoculation with the ΔhrpB mutant strain generates a hostile environment for subsequent plant colonization by a virulent strain of R. solanacearum.
authors.affiliation: INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.|CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.|Department of International Cooperation, Chinese Academy of Agricultural Sciences, 12 Zhongguancun South Street, Beijing 100081, China.
authors.forename: Dong Xin
authors.initials: DX
authors.lastname: Feng
authors.affiliation: INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.|CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Tasset
authors.affiliation: INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.|CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Hanemian
authors.affiliation: INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.|CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Barlet
authors.affiliation: College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Hu
authors.affiliation: INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.|CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Trémousaygue
authors.affiliation: INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.|CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Deslandes
authors.affiliation: INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.|CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Marco
mesh_terms: D000040:Abscisic Acid / Q000096:biosynthesis*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics; D060467:Disease Resistance; D018506:Gene Expression Regulation, Plant; D054884:Host-Pathogen Interactions / Q000235:genetics*; D010749:Phosphoprotein Phosphatases / Q000235:genetics; D010935:Plant Diseases / Q000517:prevention & control*; D044224:Pseudomonas syringae / Q000502:physiology; D043368:Ralstonia solanacearum / Q000235:genetics*; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D000040:Abscisic Acid; C087434:ABI1 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases