Diversity of Phytophthora Species in Costa Rica's Tropical Forest

The fungus-like organism Phytophthora includes more than 130 species, most of which are destructive plant pathogens. Information about the occurrence and diversity of Phytophthora species in forest and protected areas are largely unknown. The purpose of this study was to fill in the scientific gap in species biodiversity by conducting a survey in tropical forest ecosystems. The survey was conducted at 10 sites across Costa Rica. Leaves with lesions attached to live plants (LP), fallen from tree canopies (LF), submerged in forest streams (LS) and soil was sampled. Isolate identification was based on a multi-locus (4 mitochondrial and 4 nuclear) phylogeny, and examination of morphological features. In total 258 isolates were characterized into 21 species: eight known and 13 novel species. Phylogenetically, species discovered were placed in seven different clades and clade 9 included the most number of species. Species were more common in transitional forests. The number of unknown species discovered suggests that tropical forests are a “hotspot “for Phytophthora diversity.