This work will report the characterization of the Phytophthora cinnamomi NPP1 gene responsible for the infection of Castaneasativa roots and will characterize the mechanisms of interaction between Phytophthora cinnamomi and Castanea sativa, by gene silencing NPP1 from Phytophthora cinnamomi mediated by RNAi. The gene discussed is ENPP1; the disease is infection.