title: MYB72 is required in early signaling steps of rhizobacteria-induced systemic resistance in Arabidopsis.
abstract: Colonization of Arabidopsis thaliana roots by nonpathogenic Pseudomonas fluorescens WCS417r bacteria triggers a jasmonate/ethylene-dependent induced systemic resistance (ISR) that is effective against a broad range of pathogens. Microarray analysis revealed that the R2R3-MYB-like transcription factor gene MYB72 is specifically activated in the roots upon colonization by WCS417r. Here, we show that T-DNA knockout mutants myb72-1 and myb72-2 are incapable of mounting ISR against the pathogens Pseudomonas syringae pv tomato, Hyaloperonospora parasitica, Alternaria brassicicola, and Botrytis cinerea, indicating that MYB72 is essential to establish broad-spectrum ISR. Overexpression of MYB72 did not result in enhanced resistance against any of the pathogens tested, demonstrating that MYB72 is not sufficient for the expression of ISR. Yeast two-hybrid analysis revealed that MYB72 physically interacts in vitro with the ETHYLENE INSENSITIVE3 (EIN3)-LIKE3 transcription factor EIL3, linking MYB72 function to the ethylene response pathway. However, WCS417r activated MYB72 in ISR-deficient, ethylene-insensitive ein2-1 plants. Moreover, exogenous application of the ethylene precursor 1-aminocyclopropane-1-carboxylate induced wild-type levels of resistance in myb72-1, suggesting that MYB72 acts upstream of ethylene in the ISR pathway. Collectively, this study identified the transcriptional regulator MYB72 as a novel ISR signaling component that is required in the roots during early signaling steps of rhizobacteria-mediated ISR.
authors.affiliation: Graduate School Experimental Plant Sciences, Plant-Microbe Interactions, Institute of Environmental Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
authors.forename: Sjoerd
authors.initials: S
authors.lastname: Van der Ent
authors.forename: Bas W M
authors.initials: BW
authors.lastname: Verhagen
authors.forename: Ronald
authors.initials: R
authors.lastname: Van Doorn
authors.forename: Daniel
authors.initials: D
authors.lastname: Bakker
authors.forename: Maarten G
authors.initials: MG
authors.lastname: Verlaan
authors.forename: Michiel J C
authors.initials: MJ
authors.lastname: Pel
authors.forename: Ruth G
authors.initials: RG
authors.lastname: Joosten
authors.forename: Marcel C G
authors.initials: MC
authors.lastname: Proveniers
authors.forename: L C
authors.initials: LC
authors.lastname: Van Loon
authors.forename: Jurriaan
authors.initials: J
authors.lastname: Ton
authors.forename: Corné M J
authors.initials: CM
authors.lastname: Pieterse
mesh_terms: D000085:Acetates / Q000378:metabolism; D000598:Amino Acids, Cyclic / Q000378:metabolism; D017360:Arabidopsis / Q000382:microbiology / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005936:Glucans / Q000378:metabolism; D016254:Mutagenesis, Insertional; D054883:Oxylipins / Q000378:metabolism; D018517:Plant Roots / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D011551:Pseudomonas fluorescens / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D000085:Acetates; D000598:Amino Acids, Cyclic; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D004268:DNA-Binding Proteins; C500268:EIL3 protein, Arabidopsis; D005030:Ethylenes; D005936:Glucans; C530164:Myb72 protein, Arabidopsis; D054883:Oxylipins; D014157:Transcription Factors; C023863:1-aminocyclopropane-1-carboxylic acid; C072239:methyl jasmonate; C048306:callose; C036216:ethylene