The Arabidopsis transcriptional repressor ERF9 participates in resistance against necrotrophic fungi

• Published in: Plant science (Limerick) Vol. 213; pp. 79 - 87
• Main Authors: Maruyama, Yosuke, Yamoto, Natsuko, Suzuki, Yuya, Chiba, Yukako, Yamazaki, Ken-ichi, Sato, Takeo, Yamaguchi, Junji
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 01.12.2013
• Subjects: Arabidopsis; Arabidopsis - genetics; Arabidopsis - immunology; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; AtERF9; Biotic stress; Botrytis - physiology; Botrytis cinerea; cell death; Cell Nucleus - metabolism; Cyclopentanes - metabolism; Defensins - genetics; Defensins - metabolism; Disease Resistance; DREB1/CBF family; EAR motif; ethylene; Ethylenes - metabolism; fungi; Gene Expression; gene expression regulation; Gene Expression Regulation, Plant; Gene Knockout Techniques; gene overexpression; genes; hypersensitive response; jasmonic acid; knockout mutants; Models, Molecular; Oxylipins - metabolism; Pathogen resistance; Plant Diseases - immunology; Plant Diseases - microbiology; Plant Growth Regulators - metabolism; Plants, Genetically Modified; Promoter Regions, Genetic - genetics; Pseudomonas syringae - physiology; salicylic acid; Salicylic Acid - metabolism; Sequence Deletion; Signal Transduction; transcription (genetics); Transcription Factors - genetics; Transcription Factors - metabolism; Pathogen resistance; Biotic stress; EAR motif; DREB1/CBF family; AtERF9
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/j.plantsci.2013.08.008

•Arabidopsis DEAR1 overexpressor showed enhanced resistance to Botrytis cinerea.•Knockout mutants of ERF9 showed transcriptional promotion of PDF1.2 gene.•ERF9 was bound to promoters of PDH1.2 gene and had the trans-repression activity.•ERF9 participates in plant defense against necrotic fungi mediated by the DEAR1. 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.