Identification of Phytophthora spp. (Oomycota, Peronospora) as a causal agent of stem rot and dieback in fig trees (Ficus carica var. “Brown Turkey”) of Costa Rica

This research describes the morphological and molecular identification of Phytophthoraspp. from fig (Ficus carica var. “brown turkey”) stem and shoot samples, infected in experimental fields located in the Pacific coastal region, in the county of Turrubares, at the province of San José, Costa Rica. The study was performed in the Centro de Investigación en Biotecnología and the Laboratorio Institucional de Microscopíaof the Instituto Tecnológico de Costa Rica, by using symptomatic tree samples, from where the microorganisms of interest were isolated with V8 + Benomil (2g/l) culture medium. Growth of a cottonlike, starred and radiated micelia was observed. Through optical microscopy (OM) and Scanning Electron Microscopy (SEM) techniques, it was possible to determine the presence of spongarium and chlamydospores which are common traits of the Phytophthora genus. Additionally, a high quality DNA sample was obtained for the analysis through ITS markers reported for the Phytophthora genus. With the amplification of the IT’S region of the rDNA with the A2 and I2 primers, the presence of Phytophthora spp. was confirmed. The digestion of the ITS amplicon obtained with the Msp I, Rsa I and Taq I enzymes, complemented with the bioinformatic analysis of the amplified sequences allowed to confirm the presence of P. cinnamomi in the stem and P. palmivora in the shoots; being the causal agent of the fig rot.