Caracterización e identificación molecular de agentes patógenos en el cultivo de pitahaya en Ecuador

Abstract

Pitahaya cultivation has become highly significant in several countries, including Ecuador. A major constraint is the incidence of pests and diseases that affect yield. These are caused by phytopathogenic agents—including fungi and bacteria—that have been reported elsewhere and can lead to substantial economic losses. However, there is limited research in Ecuador regarding these microorganisms and their impact on the crop. Therefore, this project aimed to characterize and identify them using morphological and molecular studies to establish baseline data on their biology. Samples of affected pitahaya tissue were collected from various locations across the country; the pathogens present were isolated and identified, with a specific focus on two genera: *Phytophthora* sp. and *Diaporthe* sp. Pure cultures were obtained from three isolates of each, and their growth behavior was evaluated in incubators set at 24°C, 28°C, and 30°C under LED lighting. Additionally, DNA was extracted from each isolate for subsequent molecular identification. The results showed that the highest growth rate for most isolates occurred at 30°C; however, neither temperature nor isolate type significantly influenced the growth of either pathogen. There was little morphological variation among the evaluated isolates; all formed both asexual and sexual reproductive structures, with a predominance of zoospores and alpha-conidia. The information obtained lays the groundwork for future studies to determine the pathogenicity of these phytopathogens.