The sustainable fungicide choline pelargonate inhibits Botrytis cinerea and Phytophthora infestans growth by altering membrane structure and lipid content

Botrytis cinerea and Phytophthora infestans are two of the most widespread phytopathogens worldwide and are mainly controlled by the frequent application of synthetic chemical fungicides. Sustainable alternatives are required to reduce the possible negative effects on human health and the environment. This study aimed to characterize the mechanism of action of the sustainable fungicide choline pelargonate (CP) against B. cinerea and P. infestansin vitro. CP inhibited mycelial growth and spore germination of B. cinerea and P. infestans, causing the leakage of electrolytes and nucleic acids with dose-dependent effects. Ultrastructural alterations of the plasma membrane and cytoplasm were found in B. cinerea and P. infestans cells, with negative impacts on membrane functionality. Moreover, CP altered the content of free fatty acid, phosphatidic acid, phosphatidylcholine, phosphatidylethanolamine, and triglyceride lipid classes in B. cinerea and P. infestans mycelia, as a possible perturbation of lipid metabolism and stimulation of lipid hydrolysis. Pelargonic acid was partially incorporated into triglyceride lipids, suggesting attempted detoxification mechanisms in both phytopathogens. In conclusion, CP is a choline carboxylate with promising inhibitory activity against phytopathogens.