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.
Original language | English |
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Pages (from-to) | 2367-2386 |
Number of pages | 20 |
Journal | Journal of Experimental Botany |
Volume | 67 |
Issue number | 8 |
DOIs | |
Publication status | Published - Apr 2016 |
Keywords
- Amino Acid Motifs
- Arabidopsis
- Arabidopsis Proteins
- Co-Repressor Proteins
- Cyclopentanes
- DNA, Bacterial
- Disease Resistance
- Disease Susceptibility
- Flowers
- Fusarium
- Gene Expression Regulation, Plant
- Genes, Plant
- Models, Biological
- Mutagenesis, Insertional
- Mutation
- Oligonucleotide Array Sequence Analysis
- Oxylipins
- Phenotype
- Plant Diseases
- Plants, Genetically Modified
- Protein Binding
- Pseudomonas syringae
- RNA, Messenger
- Repressor Proteins
- Up-Regulation
- Journal Article
- Research Support, Non-U.S. Gov't