title: Arabidopsis MYC Transcription Factors Are the Target of Hormonal Salicylic Acid/Jasmonic Acid Cross Talk in Response to Pieris brassicae Egg Extract.
abstract: Arabidopsis (Arabidopsis thaliana) plants recognize insect eggs and activate the salicylic acid (SA) pathway. As a consequence, expression of defense genes regulated by the jasmonic acid (JA) pathway is suppressed and larval performance is enhanced. Cross talk between defense signaling pathways is common in plant-pathogen interactions, but the molecular mechanism mediating this phenomenon is poorly understood. Here, we demonstrate that egg-induced SA/JA antagonism works independently of the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factor ORA59, which controls the ERF branch of the JA pathway. In addition, treatment with egg extract did not enhance expression or stability of JASMONATE ZIM-domain transcriptional repressors, and SA/JA cross talk did not involve JASMONATE ASSOCIATED MYC2-LIKEs, which are negative regulators of the JA pathway. Investigating the stability of MYC2, MYC3, and MYC4, three basic helix-loop-helix transcription factors that additively control jasmonate-related defense responses, we found that egg extract treatment strongly diminished MYC protein levels in an SA-dependent manner. Furthermore, we identified WRKY75 as a novel and essential factor controlling SA/JA cross talk. These data indicate that insect eggs target the MYC branch of the JA pathway and uncover an unexpected modulation of SA/JA antagonism depending on the biological context in which the SA pathway is activated.
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: André
authors.initials: A
authors.lastname: Schmiesing
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Aurélia
authors.identifier: 0000-0002-7682-655X
authors.initials: A
authors.lastname: Emonet
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Caroline
authors.initials: C
authors.lastname: Gouhier-Darimont
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland philippe.reymond@unil.ch.
authors.forename: Philippe
authors.identifier: 0000-0002-3341-6200
authors.initials: P
authors.lastname: Reymond
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000378:metabolism* / Q000469:parasitology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism*; D007915:Lepidoptera; D008954:Models, Biological; D010063:Ovum / Q000378:metabolism*; D054883:Oxylipins / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism*; D012326:RNA Splicing / Q000235:genetics; D020156:Salicylic Acid / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; D014157:Transcription Factors; C011006:jasmonic acid; D020156:Salicylic Acid