title: Characterization of a JAZ7 activation-tagged Arabidopsis mutant with increased susceptibility to the fungal pathogen Fusarium oxysporum.
abstract: In Arabidopsis, jasmonate (JA)-signaling plays a key role in mediating Fusarium oxysporum disease outcome. However, the roles of JASMONATE ZIM-domain (JAZ) proteins that repress JA-signaling have not been characterized in host resistance or susceptibility to this pathogen. Here, we found most JAZ genes are induced following F. oxysporum challenge, and screening T-DNA insertion lines in Arabidopsis JAZ family members identified a highly disease-susceptible JAZ7 mutant (jaz7-1D). This mutant exhibited constitutive JAZ7 expression and conferred increased JA-sensitivity, suggesting activation of JA-signaling. Unlike jaz7 loss-of-function alleles, jaz7-1D also had enhanced JA-responsive gene expression, altered development and increased susceptibility to the bacterial pathogen PstDC3000 that also disrupts host JA-responses. We also demonstrate that JAZ7 interacts with transcription factors functioning as activators (MYC3, MYC4) or repressors (JAM1) of JA-signaling and contains a functional EAR repressor motif mediating transcriptional repression via the co-repressor TOPLESS (TPL). We propose through direct TPL recruitment, in wild-type plants JAZ7 functions as a repressor within the JA-response network and that in jaz7-1D plants, misregulated ectopic JAZ7 expression hyper-activates JA-signaling in part by disturbing finely-tuned COI1-JAZ-TPL-TF complexes.
authors.affiliation: CSIRO Agriculture, Queensland Bioscience Precinct, St. Lucia, Queensland 4067, Australia louise.thatcher@csiro.au.
authors.forename: Louise F
authors.initials: LF
authors.lastname: Thatcher
authors.affiliation: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK.
authors.forename: Volkan
authors.initials: V
authors.lastname: Cevik
authors.affiliation: College of Life and Environmental Sciences, University of Exeter, UK.
authors.forename: Murray
authors.initials: M
authors.lastname: Grant
authors.affiliation: College of Biological Sciences, China Agricultural University, Beijing 100093, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhai
authors.affiliation: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK.
authors.forename: Jonathan D G
authors.initials: JD
authors.lastname: Jones
authors.affiliation: CSIRO Agriculture, Queensland Bioscience Precinct, St. Lucia, Queensland 4067, Australia.
authors.forename: John M
authors.initials: JM
authors.lastname: Manners
authors.affiliation: CSIRO Agriculture, Queensland Bioscience Precinct, St. Lucia, Queensland 4067, Australia The Queensland Alliance for Agriculture & Food Innovation (QAAFI), The University of Queensland, Queensland Bioscience Precinct, Brisbane, Queensland 4072, Australia.
authors.forename: Kemal
authors.initials: K
authors.lastname: Kazan
mesh_terms: D020816:Amino Acid Motifs; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D056970:Co-Repressor Proteins / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology; D004269:DNA, Bacterial / Q000235:genetics; D060467:Disease Resistance / Q000187:drug effects; D004198:Disease Susceptibility; D035264:Flowers / Q000187:drug effects / Q000502:physiology; D005670:Fusarium / Q000187:drug effects / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D008954:Models, Biological; D016254:Mutagenesis, Insertional / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D054883:Oxylipins / Q000494:pharmacology; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology*; D030821:Plants, Genetically Modified; D011485:Protein Binding / Q000187:drug effects; D044224:Pseudomonas syringae / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D056970:Co-Repressor Proteins; D003517:Cyclopentanes; D004269:DNA, Bacterial; C000602233:JAZ7 protein, Arabidopsis; D054883:Oxylipins; D012333:RNA, Messenger; D012097:Repressor Proteins; C036483:T-DNA; C011006:jasmonic acid
keywords: Defense; ERF-associated amphiphilic repressor; Pseudomonas syringae; TOPLESS; fungal pathogen; methyl jasmonate; transcriptional repression.