NPR1 and infection: NPR1, a key gen regulator for transducing the SA signaling and activating PR gene expression in the pathway (Dong, 2004; Grant and Lamb, 2006), and both exogenous SA application and pathogen infection may lead to enhanced expression of the NPR1 gene of the SAR pathway in plants (Cao et al., 1997; Ryals et al., 1997).