Expression profiles of the Arabidopsis WRKY gene superfamily during plant defense response.
WRKY proteins are a recently identified class of DNA-binding proteins that recognize the TTGAC(C/T) W-box elements found in the promoters of a large number of plant defense-related genes. With oligo molecules containing the W-box sequences as probes, we detected a number of WRKY DNA-binding activities in Arabidopsis that were induced by salicylic acid (SA). Search of the Arabidopsis genome identifies 72 genes encoding proteins characteristic of WRKY DNA-binding transcription factors that can be divided into three groups based on the number and structures of their WRKY zinc-finger motifs. Northern blotting analysis revealed that 49 of the 72 AtWRKY genes were differentially regulated in the plants infected by an avirulent strain of the bacterial pathogen Pseudomonas syringae or treated by SA. These pathogen- and/or SA-regulated WRKY genes can be further categorized into groups based on their expression patterns in both wild-type plants and mutants defective in defense signaling pathways. Inspection of the 5' sequences upstream of the predicated translation start sites revealed a substantial enrichment of W boxes in the promoters of pathogen- and/or SA-regulated Arabidopsis WRKY genes. These results suggest that defense-regulated expression of WRKY genes involves extensive transcriptional activation and repression by its own members of the transcription factor superfamily.
Dong
Jixin
J
Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, ID 83844-3052, USA.
Chen
Chunhong
C
Chen
Zhixiang
Z
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000382:microbiology / Q000502:physiology; D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018745:Genome, Plant; D007113:Immunity, Innate / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D015345:Oligonucleotide Probes; D010935:Plant Diseases / Q000382:microbiology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D011549:Pseudomonas / Q000472:pathogenicity*; D020156:Salicylic Acid / Q000494:pharmacology; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D015345:Oligonucleotide Probes; D010940:Plant Proteins; D014157:Transcription Factors; C499621:ZAP1 protein, Arabidopsis; D020156:Salicylic Acid