Maria Gabriela Mariduena-Zavala, Andrea Freire-Penaherrera and Juan Manuel Cevallos-Cevallos
Escuela Superior Politecnica del Litoral, Ecuador
Potato production is continuously being threatened by Phytophthora infestans, the most important potato pathogen worldwide. Applications of phenylamide fungicides including metalaxyl have been used to control this pathogen, causing the development of fungicide resistance in P. infestans. Despite the importance of the disease, no metabolomics-based characterization of fungicide resistance development in P. infestans has been reported. Isolates of P. infestans were obtained from the most important potato production areas in Ecuador. The resistance of Phytophthora infestans isolates to metalaxyl was evaluated in vitro and the GC-MS metabolite profile of all isolates was assessed at 0, 0.5 and 100 mg/L of metalaxyl. All metabolites were mapped to potential pathways using KEGG pathway mapping with Pseudocercospora fijiensis as the model organism. Only 30% of the isolates tested were sensitive to the low doses of metalaxyl and a total of 49 metabolites were differentially expressed in resistant isolates growing in the presence of the fungicide. Metabolites such as hexadecanoic and octadecanoic acids; glucose, fructose, proline, valine, butanedioic and propionic acids were overexpressed in resistant isolates. Potential resistance-related metabolic pathways were mostly involved in the regulation of the pathogenâ??s membrane fluidity and included the fatty acid biosynthesis as well as the glycerophospholipid metabolism pathways. No metalaxyl residues were found in resistant isolates, suggesting that the fungicide was not able to penetrate the membranes.
Maria Gabriela Mariduena-Zavala is an Agricultural Engineer from Ecuador with a Master's degree in Biotechnology. She has been involved in Agricultural Research and carried out various studies in the Phytopathology department at Espol University in Guayaquil, Ecuador. Her research has been directed towards the use of omics tools for the characterization of pathogenic fungi from the main crops in Ecuador. Among her studies, the morphological and genetic characterizations of Moniliophthora species from cocoa crops in Ecuador as well as the investigation of metabolomics profiles of isolates resistant to fungicides including Mycosphaerella fijiensis and Phytophthora infestans are noteworthy. Her current studies focus on “The use of metabolomics and metagenomics techniques for understanding of the behavior of fungal communities”.
Email: gmaridue@espol.edu.ec
