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Characterization of a JAZ7 activation-tagged Arabidopsis mutant with increased susceptibility to the fungal pathogen Fusarium oxysporum.
- Source :
-
Journal of Experimental Botany . Apr2016, Vol. 67 Issue 8, p2367-2386. 20p. 2 Color Photographs, 3 Diagrams, 1 Chart, 9 Graphs. - Publication Year :
- 2016
-
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 Pst DC3000 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 wildtype 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. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00220957
- Volume :
- 67
- Issue :
- 8
- Database :
- Academic Search Index
- Journal :
- Journal of Experimental Botany
- Publication Type :
- Academic Journal
- Accession number :
- 114127709
- Full Text :
- https://doi.org/10.1093/jxb/erw040