This family consists of several NPP1 like necrosis inducing proteins from oomycetes, fungi and bacteria. Infiltration of NPP1 into leaves of Arabidopsis thaliana plants result in transcript accumulation of pathogenesis-related (PR) genes, production of ROS and ethylene, callose apposition, and HR-like cell death [1].

1: NPP1, a Phytophthora-associated trigger of plant defense in parsley and Arabidopsis. Fellbrich G, Romanski A, Varet A, Blume B, Brunner F, Engelhardt S, Felix G, Kemmerling B, Krzymowska M, Nurnberger T; Plant J 2002;32:375-390. PMID:12410815

2: Expression of a Phytophthora sojae necrosis-inducing protein occurs during transition from biotrophy to necrotrophy. Qutob D, Kamoun S, Gijzen M; Plant J 2002;32:361-373. PMID:12410814