Arabidopsis WRKY46 coordinates with WRKY70 and WRKY53 in basal resistance against pathogen Pseudomonas syringae.
The WRKY transcription factors are involved in plant resistance against both biotrophic and necrotrophic pathogens. Arabidopsis WRKY46 is specifically induced by salicylic acid (SA) and biotrophic pathogen Pseudomonas syringae infection. To determine its possible roles in plant defense and elucidate potential functional redundancy with structurally related WRKY70 and WRKY53, we examined loss-of-function T-DNA insertion single, double and triple mutants, as well as gain-of-function transgenic WRKY46 over-expressing plants in response to P. syringae. WRKY46 over-expressing plants were more resistant to P. syringae. In contrast, pathogen-infected wrky46wrky70, wrky46wrky53 double mutants and wrky46wrky70wrky53 triple mutants showed increased susceptibility to this pathogen, with increased bacterial growth and more severe disease symptoms. The contrasting responses of gain-of-function plants and loss-of-function mutants were correlated with increased or reduced expression of defense-related PR1 gene. Expression studies of WRKY46, WRKY70, and WRKY53 in various defense-signaling mutants suggested that they are partially involved in SA-signaling pathway. In addition, our findings demonstrated negative cross-regulation among these three genes. These results indicate that WRKY46, WRKY70, and WRKY53 positively regulate basal resistance to P. syringae; and that they play overlapping and synergetic roles in plant basal defense.
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
Yanru
Y
Hu
Qiuyan
Q
Dong
Diqiu
D
Yu
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D060467:Disease Resistance; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D030821:Plants, Genetically Modified; D044224:Pseudomonas syringae / Q000502:physiology*; D020156:Salicylic Acid / Q000494:pharmacology; D015398:Signal Transduction / Q000276:immunology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D010937:Plant Growth Regulators; D014157:Transcription Factors; C579612:WRKY46 protein, Arabidopsis; C496136:WRKY53 protein, Arabidopsis; C487183:WRKY70 protein, Arabidopsis; D020156:Salicylic Acid