Two Clonal Species of Phytophthora Associated to Solanaceous Crops Coexist in Central and Southern Colombia

Abstract

In Colombia, late blight is considered one of the most limiting diseases on potato and tomato production. Recently, a new Phytophthora species, P. betacei, was described infecting tree tomato crops in the south of Colombia. However, the distribution and the host range of this new emerging pathogen in the country are unknown. The main aims of this study were to determine if this novel species is confined to the south of Colombia, to assess if P. betacei represents a genetically uniform clone across Colombia and to determine if in all regions there is a clear differentiation between the two Phytophthora species. Therefore, we characterized Phytophthora isolates obtained from tree tomato and potato crops in a central region of Colombia and compared them with the strains from the south. Initially, we evaluated the genetic differentiation among Phytophthora strains obtained from tree tomato and potato crops using simple sequence repeat markers. Results showed a strong population structure between P. infestans and P. betacei. However, we did not detect any genetic differentiation within P. infestans or P. betacei populations from different regions. Furthermore, we detected significant morphological differences among the species based on growth and sporangial morphology measurements. We also showed that strains of Phytophthora spp. are predominantly of the A1 mating type and belong to EC-1 and EC-3 clonal lineages for P. infestans and P. betacei, respectively. Our results describe the expanded geographical range of the new species of P. betacei in the central region of Colombia.