title: The Mediator subunit SFR6/MED16 controls defence gene expression mediated by salicylic acid and jasmonate responsive pathways.
abstract: • Arabidopsis SENSITIVE TO FREEZING6 (SFR6) controls cold- and drought-inducible gene expression and freezing- and osmotic-stress tolerance. Its identification as a component of the MEDIATOR transcriptional co-activator complex led us to address its involvement in other transcriptional responses. • Gene expression responses to Pseudomonas syringae, ultraviolet-C (UV-C) irradiation, salicylic acid (SA) and jasmonic acid (JA) were investigated in three sfr6 mutant alleles by quantitative real-time PCR and susceptibility to UV-C irradiation and Pseudomonas infection were assessed. • sfr6 mutants were more susceptible to both Pseudomonas syringae infection and UV-C irradiation. They exhibited correspondingly weaker PR (pathogenesis-related) gene expression than wild-type Arabidopsis following these treatments or after direct application of SA, involved in response to both UV-C and Pseudomonas infection. Other genes, however, were induced normally in the mutants by these treatments. sfr6 mutants were severely defective in expression of plant defensin genes in response to JA; ectopic expression of defensin genes was provoked in wild-type but not sfr6 by overexpression of ERF5. • SFR6/MED16 controls both SA- and JA-mediated defence gene expression and is necessary for tolerance of Pseudomonas syringae infection and UV-C irradiation. It is not, however, a universal regulator of stress gene transcription and is likely to mediate transcriptional activation of specific regulons only.
authors.affiliation: Durham Centre for Crop Improvement Technology, School of Biological and Biomedical Sciences, Durham University, Durham, UK.
authors.forename: Deepthi L
authors.initials: DL
authors.lastname: Wathugala
authors.forename: Piers A
authors.initials: PA
authors.lastname: Hemsley
authors.forename: Caroline S
authors.initials: CS
authors.lastname: Moffat
authors.forename: Pieter
authors.initials: P
authors.lastname: Cremelie
authors.forename: Marc R
authors.initials: MR
authors.lastname: Knight
authors.forename: Heather
authors.initials: H
authors.lastname: Knight
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism* / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D056892:Mediator Complex / Q000235:genetics / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism* / Q000494:pharmacology; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D044224:Pseudomonas syringae / Q000472:pathogenicity; D020156:Salicylic Acid / Q000378:metabolism* / Q000494:pharmacology; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D056892:Mediator Complex; D054883:Oxylipins; C575423:SFR6 protein, Arabidopsis; D015534:Trans-Activators; C011006:jasmonic acid; D020156:Salicylic Acid