Ecological speciation within the Phytophthora group

Abstract

Over the past few years, symptoms akin to late blight disease have been reported on a variety of crop plants in South America. Despite the economic importance of these crops, the causal agents of the diseases belonging to the genus Phytophthora have not been completely characterized. In this study, we used an integrative approach that leveraged morphological, ecological, and genetic approaches to explore cryptic speciation within P. infestans sensu lato. We described a new Phytophthora species collected in Colombia from tree tomato (Solanum betaceum), a semi-domesticated fruit. All morphological traits and population genetic analyses, using microsatellite data and a reduced representation of single nucleotide polymorphism (SNP) data, support the description of the new species, Phytophthora betacei sp. nov. We have demonstrated that ecological differences are important in the persistence of P. infestans and P. betacei as genetically isolated units across an overlapping area in the northern Andes.