Secreted effector that interacts with and inhibits the pathogenesis-related papain-like cysteine proteases C14, PIP1 and RCR3 of host plants (PubMed:17085509, PubMed:19171904, PubMed:20940351). Inhibition of host proteases by a pathogen extracellular protease inhibitor forms a specific type of defense-counterdefense mechanism between plants and microbial pathogens (PubMed:17085509, PubMed:19171904, PubMed:20940351). Interacts with the host papain-like cysteine protease PIP1 (PubMed:17085509). Interacts with the host papain-like cysteine protease RCR3 (PubMed:19171904). Interacts with the host papain-like cysteine protease C14 (PubMed:20940351). Localizes to host apoplast where it targets defense proteases for inhibition. Expression is up-regulated during infection of host tomato. Belongs to the cystatin family.