NPR1 and infection: Under unchallenged conditions, NPR1 is present in the cytosol as a stable oligomer (Mou et al., 2003); however, upon pathogen infection, monomeric forms of NPR1 are transferred to the nucleus to bind the TGA family of transcription factors, activating the expression of defense-related genes, such as PR1 and WRKY (Zhang et al., 1999; Mou et al., 2003; Wang et al., 2006).