Involved in defense response against the bacterial blight disease caused by Xanthomonas oryzae pv. oryzae (Xoo). Plants expressing an NPR3/NH3 transgene driven by its native promoter show enhanced resistance to the Xoo pathogen, and exhibit elevated sensitivity to benzothiadiazole (BTH) treatment and enhanced induction of defense-related genes upon treatment with BTH (PubMed:20561248). Intriguingly, constitutive over-expression of NPR3/NH3 with a ubiquitin promoter does not confer disease resistance to Xoo (PubMed:17309686). Interacts with TGA2.1, TGA2.2, TGA2.3, LG2, TGAL1, TGAL4, NRR, RH1, RH2 and RH3.