Evidence for an Important Role of WRKY DNA Binding Proteins in the Regulation of NPR1 Gene Expression

Citations Over TimeTop 1% of 2001 papers

Abstract

The Arabidopsis NPR1 gene is a positive regulator of inducible plant disease resistance. Expression of NPR1 is induced by pathogen infection or treatment with defense-inducing compounds such as salicylic acid (SA). Transgenic plants overexpressing NPR1 exhibit enhanced resistance to a broad spectrum of microbial pathogens, whereas plants underexpressing the gene are more susceptible to pathogen infection. These results suggest that regulation of NPR1 gene expression is important for the activation of plant defense responses. In the present study, we report the identification of W-box sequences in the promoter region of the NPR1 gene that are recognized specifically by SA-induced WRKY DNA binding proteins from Arabidopsis. Mutations in these W-box sequences abolished their recognition by WRKY DNA binding proteins, rendered the promoter unable to activate a downstream reporter gene, and compromised the ability of NPR1 to complement npr1 mutants for SA-induced defense gene expression and disease resistance. These results provide strong evidence that certain WRKY genes act upstream of NPR1 and positively regulate its expression during the activation of plant defense responses. Consistent with this model, we found that SA-induced expression of a number of WRKY genes was independent of NPR1.

Related Papers

• → Enhancement of induced disease resistance by simultaneous activation of salicylate- and jasmonate-dependent defense pathways in Arabidopsis thaliana(2000)606 cited
• → Salicylic Acid in Plant Disease Resistance(2007)62 cited
• → The Arabidopsis NIMIN proteins affect NPR1 differentially(2013)62 cited
• Systemic Acquired Resistance and Signal Transduction in Plant(2003)
• Systemic Acquired Resistance and Signal Transduction in Plant(2003)