title: The Arabidopsis transcriptional repressor ERF9 participates in resistance against necrotrophic fungi.
abstract: Complex plant defenses that include the hypersensitive response (HR) are mediated by plant hormones, such as salicylic acid (SA), jasmonic acid (JA) and ethylene. We previously isolated the Arabidopsis DEAR1 (DREB AND EAR MOTIF PROTEIN 1) regulator and showed that its overexpression DEAR1 (DEAR1ox) resulted in a dwarf phenotype and lesion-like cell death, accompanied by elevated expression of PR (PATHOGENESIS-RELATED) genes. Here, we show that transgenic Arabidopsis overexpressing DEAR1 (DEAR1ox) has enhanced resistance to the necrotrophic fungus Botrytis cinerea (B. cinerea). This result indicates that DEAR1 represses negative regulators of plant defense responses, including transcriptional repressors belonging to the ERF (ETHYLEN RESPONSE FACTOR) family. Knockout mutants of ERF9 (erf9), which were down-regulated in DEAR1ox plants, showed transcriptional promotion of PDF1.2 (PATHOGEN-INDUCIBLE PLANT DEFENSIN) genes, which serve as positive markers for the ethylene/jasmonic acid (JA) signaling pathway and provide enhanced resistance to B. cinerea. Biochemical assays demonstrated that the ERF9 in capable of binding to the GCC box, a cis-element contained in the promoters of the PDF1.2 gene that possesses trans-repression activity. Moreover, infection with B. cinerea resulted in the promotion of the PDF1.2 expression, coinciding with suppression of the ERF9 gene under the control of the DEAR1 gene. These results indicate that the transcriptional repressor ERF9 participates in plant defense mechanisms against necrotic fungi mediated by the DEAR1-dependent ethylene/JA signaling pathway.
authors.affiliation: Faculty of Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan. Electronic address: ymaruyama@mail.sci.hokudai.ac.jp.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Maruyama
authors.forename: Natsuko
authors.initials: N
authors.lastname: Yamoto
authors.forename: Yuya
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Yukako
authors.initials: Y
authors.lastname: Chiba
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Yamazaki
authors.forename: Takeo
authors.initials: T
authors.lastname: Sato
authors.forename: Junji
authors.initials: J
authors.lastname: Yamaguchi
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D020171:Botrytis / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism; D023082:Defensins / Q000235:genetics / Q000378:metabolism; D060467:Disease Resistance; D005030:Ethylenes / Q000378:metabolism; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D008958:Models, Molecular; D054883:Oxylipins / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D044224:Pseudomonas syringae / Q000502:physiology; D020156:Salicylic Acid / Q000378:metabolism; D017384:Sequence Deletion; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D023082:Defensins; D005030:Ethylenes; D054883:Oxylipins; D010937:Plant Growth Regulators; D020156:Salicylic Acid; D014157:Transcription Factors; C588311:DEAR1 protein, Arabidopsis; C588310:ERF9 protein, Arabidopsis; C487542:At5g44420 protein, Arabidopsis; C011006:jasmonic acid; C036216:ethylene
keywords: AtERF9; Biotic stress; DREB1/CBF family; EAR motif; Pathogen resistance