title: Antagonistic interaction between abscisic acid and jasmonate-ethylene signaling pathways modulates defense gene expression and disease resistance in Arabidopsis.
abstract: The plant hormones abscisic acid (ABA), jasmonic acid (JA), and ethylene are involved in diverse plant processes, including the regulation of gene expression during adaptive responses to abiotic and biotic stresses. Previously, ABA has been implicated in enhancing disease susceptibility in various plant species, but currently very little is known about the molecular mechanisms underlying this phenomenon. In this study, we obtained evidence that a complex interplay between ABA and JA-ethylene signaling pathways regulate plant defense gene expression and disease resistance. First, we showed that exogenous ABA suppressed both basal and JA-ethylene-activated transcription from defense genes. By contrast, ABA deficiency as conditioned by the mutations in the ABA1 and ABA2 genes, which encode enzymes involved in ABA biosynthesis, resulted in upregulation of basal and induced transcription from JA-ethylene responsive defense genes. Second, we found that disruption of AtMYC2 (allelic to JASMONATE INSENSITIVE1 [JIN1]), encoding a basic helix-loop-helix Leu zipper transcription factor, which is a positive regulator of ABA signaling, results in elevated levels of basal and activated transcription from JA-ethylene responsive defense genes. Furthermore, the jin1/myc2 and aba2-1 mutants showed increased resistance to the necrotrophic fungal pathogen Fusarium oxysporum. Finally, using ethylene and ABA signaling mutants, we showed that interaction between ABA and ethylene signaling is mutually antagonistic in vegetative tissues. Collectively, our results indicate that the antagonistic interactions between multiple components of ABA and the JA-ethylene signaling pathways modulate defense and stress responsive gene expression in response to biotic and abiotic stresses.
authors.affiliation: Cooperative Research Centre for Tropical Plant Protection, University of Queensland, St. Lucia, Queensland, 4072, Australia.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Anderson
authors.forename: Ellet
authors.initials: E
authors.lastname: Badruzsaufari
authors.forename: Peer M
authors.initials: PM
authors.lastname: Schenk
authors.forename: John M
authors.initials: JM
authors.lastname: Manners
authors.forename: Olivia J
authors.initials: OJ
authors.lastname: Desmond
authors.forename: Christina
authors.initials: C
authors.lastname: Ehlert
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Maclean
authors.forename: Paul R
authors.initials: PR
authors.lastname: Ebert
authors.forename: Kemal
authors.initials: K
authors.lastname: Kazan
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D003517:Cyclopentanes / Q000378:metabolism*; D005030:Ethylenes / Q000378:metabolism*; D005670:Fusarium / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D007113:Immunity, Innate / Q000502:physiology*; D008969:Molecular Sequence Data; D054883:Oxylipins; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D015398:Signal Transduction / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D003517:Cyclopentanes; D005030:Ethylenes; C473611:MYC2 protein, Arabidopsis; D054883:Oxylipins; D015534:Trans-Activators; C011006:jasmonic acid; D000040:Abscisic Acid; C036216:ethylene; C469255:ABA2 protein, Arabidopsis; D000429:Alcohol Oxidoreductases