Efectos de extractos de hojas de Citrus latifolia (Tanaka ex Yu. Tanaka) Tanaka y Citrus aurantiifolia (Christm.) Swingle sobre la membrana y la respiración celular de Alternaria solani Sor.

Early blight is one of the main phytosanitary problems affecting the cultivation of tomato ( Solanum lycopersicum L.) and potato ( Solanum tuberosum L.). This disease is caused by Alternaria solani , whose control is basically by using synthetic fungicides. In this sense, plants are an alternative in the search for new sources of less aggressive antifungal compounds to the environment. Leaf extracts of Citrus latifolia in ethanol 70 % and Citrus aurantiifolia in methanol 70 % have proven antifungal activity against A. solani. The aim of this study was to determine the effect of these extracts on the cellular membrane and respiration of A. solani. The extracts were obtained by ultrasound-assisted extraction, and the total phenolic content was measured. The effect of the extracts on the cellular membrane and respiration was evaluated by determining the concentrations of phosphorus and potassium in the extracellular medium and the activity of the succinate dehydrogenase enzyme. The high concentrations of phosphorus and potassium found in the extracellular medium suggest damages in the permeability of the cellular membrane of A. solani. Similarly, the inactivity of the succinate dehydrogenase enzyme pointed to an inhibition of the cellular respiration of A. solani by the evaluated citrus extracts. The results obtained in this study confirmed the antifungal properties of leaf extracts of C. latifolia and C. aurantiifolia and suggested its possible use in the agro-ecological management of the causal agent of the early blight disease of tomato and potato.