Phytophthora cinnamomi is an Oomycetes associated with soil, this Oomycete is one of the most destructive species of Phytophthora, being responsible for the decline of more than 5000 ornamental, forest, or fruit plants. It can secrete a class of protein NPP1 (Phytophthora necrosis inducing protein 1), responsible for inducing necrosis in leaves and roots of plants, leading to their death. Objective This work will report the characterization of the Phytophthora cinnamomi NPP1 gene responsible for the infec tion of Castanea sativa roots and will characterize the mechanisms of interaction between Phytophthora cinnamomi and Castanea sativa, by gene silencing NPP1 from Phytophthora cinnamomi mediated by RNAi. Methods and results For silencing a part of the coding region of the NPP1 gene, was placed in the sense and antisense directions between an intron and ligated to the integrative vector pTH210. Cassette integration was confrmed by PCR and sequencing on the hygromycin-resistant Phytophthora cinnamomi transformants. Transformants obtained with the silenced
gene was used to infect Castanea sativa.
Conclusions Plants infected with these transformants showed a great reduction in disease symptoms, confrming iRNA as a potential alternative biological tool in the study of molecular factors, and in the control and management of Phytophthora
cinnamomi.
The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2019).
