Many stress mechanisms, such as antioxidative mechanisms, are known to be activated by heavy metals. The aim of this work was to investigate whether oxidative stress and related mechanisms were expressed differently in plants with different resistances to

WIPK (wound induced protein kinase) is a tobacco MAP kinase, transcripts of which are induced by mechanical wounding and TMV infection. In order to clarify the mechanisms of regulation of WIPK expression, we isolated a 1122 bp section of the promoter region of the WIPK gene and fused it to the GUS reporter gene. Histochemical staining using a transgenic line containing this construct clearly showed WIPK to be almost exclusively localized at or near the sites of wounding and necrotic lesions. To identify the responsive elements, 5′-deletion constructs containing 874, 559 and 430 bp of the promoter regions, respectively, were fused to GUS and transgenic tobacco lines containing these constructs were assayed for GUS induction upon wounding or on stimulation of a hypersensitive response (HR) after TMV infection. Measurement of enzymatic activity and Northern blot hybridization showed that the shortest promoter of 430 bp was sufficient for HR and a wound response, but that the extended region conferred a higher magnitude of response. It was thus suggested that, although the promoter region within 430 bp is essential, WIPK is regulated by multiple factors including enhancer-like elements residing beyond the core region.