The invention provides isolated NPR1 nucleic acids and their encoded proteins. The present invention provides methods and compositions relating to altering NPR1 concentration and/or composition of plants. The invention further provides recombinant expression cassettes, host cells, and transgenic plants. Additionally, the present invention provides promoter elements capable of initiating constitutive expression in a plant. Further, the present invention provides for methods for screening putative activators of a plant resistance pathway.