- NPR1 differentially interacts with members of the TGA/OBF family of transcription factors that bind an element of the PR-1 gene required for induction by salicylic acid. Zhou, J.M., Trifa, Y., Silva, H., Pontier, D., Lam, E., Shah, J., Klessig, D.F. Mol. Plant Microbe Interact. (2000)