title: A MYB transcription factor regulates very-long-chain fatty acid biosynthesis for activation of the hypersensitive cell death response in Arabidopsis.
abstract: Plant immune responses to pathogen attack include the hypersensitive response (HR), a form of programmed cell death occurring at invasion sites. We previously reported on Arabidopsis thaliana MYB30, a transcription factor that acts as a positive regulator of a cell death pathway conditioning the HR. Here, we show by microarray analyses of Arabidopsis plants misexpressing MYB30 that the genes encoding the four enzymes forming the acyl-coA elongase complex are putative MYB30 targets. The acyl-coA elongase complex synthesizes very-long-chain fatty acids (VLCFAs), and the accumulation of extracellular VLCFA-derived metabolites (leaf epidermal wax components) was affected in MYB30 knockout mutant and overexpressing lines. In the same lines, a lipid extraction procedure allowing high recovery of sphingolipids revealed changes in VLCFA contents that were amplified in response to inoculation. Finally, the exacerbated HR phenotype of MYB30-overexpressing lines was altered by the loss of function of the acyl-ACP thioesterase FATB, which causes severe defects in the supply of fatty acids for VLCFA biosynthesis. Based on these findings, we propose a model in which MYB30 modulates HR via VLCFAs by themselves, or VLCFA derivatives, as cell death messengers in plants.
authors.affiliation: Unité Mixte de Recherche 2594/441, 31320 Castanet-Tolosan cedex, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Raffaele
authors.forename: Fabienne
authors.initials: F
authors.lastname: Vailleau
authors.forename: Amandine
authors.initials: A
authors.lastname: Léger
authors.forename: Jérôme
authors.initials: J
authors.lastname: Joubès
authors.forename: Otto
authors.initials: O
authors.lastname: Miersch
authors.forename: Carine
authors.initials: C
authors.lastname: Huard
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Blée
authors.forename: Sébastien
authors.initials: S
authors.lastname: Mongrand
authors.forename: Frédéric
authors.initials: F
authors.lastname: Domergue
authors.forename: Dominique
authors.initials: D
authors.lastname: Roby
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D016923:Cell Death / Q000235:genetics; D005227:Fatty Acids / Q000096:biosynthesis*; D018506:Gene Expression Regulation, Plant; D008954:Models, Biological; D020411:Oligonucleotide Array Sequence Analysis; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D005227:Fatty Acids; C500589:Myb protein, Arabidopsis; D014157:Transcription Factors