Expression of AtWRKY33 Encoding a Pathogen- or PAMP-Responsive WRKY Transcription Factor Is Regulated by a Composite DNA Motif Containing W Box Elements

• Published in: Molecular plant-microbe interactions Vol. 20; no. 4; pp. 420 - 429
• Main Authors: Lippok, B, Birkenbihl, R.P, Rivory, G, Brummer, J, Schmelzer, E, Logemann, E, Somssich, I.E
• Format: Journal Article
• Language: English
• Published: St Paul, MN APS Press 01.04.2007; The American Phytopathological Society
• Subjects: Alternaria; Arabidopsis - genetics; Arabidopsis - immunology; Arabidopsis - microbiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - immunology; Arabidopsis thaliana; biochemical pathways; Biological and medical sciences; Cycloheximide - pharmacology; Fundamental and applied biological sciences. Psychology; gene expression; Gene Expression - drug effects; Gene Expression - radiation effects; gene expression regulation; Gene Expression Regulation, Plant; genes; Hyaloperonospora parasitica; Immunity, Innate; molecular sequence data; pathogen-associated molecular patterns; Phytopathology. Animal pests. Plant and forest protection; plant proteins; Plants, Genetically Modified; promoter regions; Promoter Regions, Genetic; protein synthesis; Protein Synthesis Inhibitors - pharmacology; resistance mechanisms; Response Elements; salicylic acid; sequence analysis; Thiadiazoles - pharmacology; transcription factors; Transcription Factors - genetics; Transcription Factors - immunology; Transcriptional Activation; Ultraviolet Rays; Salicylic acid; Altemaria; Microbiology; Arabidopsis; Gene expression; Regulation(control); pathogen-associated molecular patterns; Gene; Hyaloperonospora parasitica; Cruciferae; Protein synthesis; Dicotyledones; Angiospermae; Herbaceous plant; Spermatophyta; Transcription factor
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/mpmi-20-4-0420

WRKY transcription factors regulate distinct parts of the plant defense transcriptome. Expression of many WRKY genes themselves is induced by pathogens or pathogen-mimicking molecules. Here, we demonstrate that Arabidopsis WRKY33 responds to various stimuli associated with plant defense as well as to different kinds of phytopathogens. Although rapid pathogen-induced AtWRKY33 expression does not require salicylic acid (SA) signaling, it is dependent on PAD4, a key regulator upstream of SA. Activation of AtWRKY33 is independent of de novo protein synthesis, suggesting that it is at least partly under negative regulatory control. We show that a set of three WRKY-specific cis-acting DNA elements (W boxes) within the AtWRKY33 promoter is required for efficient pathogen- or PAMP-triggered gene activation. This strongly indicates that WRKY transcription factors are major components of the regulatory machinery modulating immediate to early expression of this gene in response to pathogen attack.