Sensitization of plant pathogenic fungi to the tebuconazole-based commercial fungicide using some analogues of natural amino acids

Commercial fungicides provide an efficient control of fungal diseases of crops. At the same time, plant pathogenic fungi can develop resistance to fungicides that results in epiphytoties and significant yield losses. The most common response of potato growers is more extensive use of fungicides associated with environmental pollution and a range of various health risks. Therefore, the search for approach preventing the development of pest resistance to fungicides is of great practical interest. A potentially new strategy to overcome or minimize this problem is an enhancement of pathogen sensitivity to fungicides using various chemical compounds. In this study, we examined several putative sensitizers chosen among structural analogues of some natural amino acids known for their inhibiting effect on the polyketide biosynthetic pathway, since polyketide mycotoxins play an important role in a pathogenicity of fungi. A possible synergism between the action of these compounds and a commercial fungicide Folicur on the growth of Phoma glomerata and Fusarium culmorum colonies was evaluated using the Limpel’s criterion. For all four compounds tested, a significant chemosensitizing effect was revealed for both non-fungicidal and sub-fungicidal concentrations that confirmed the initial hypothesis. The further screening of other amino acid analogues for their chemosensitizing activity is planned, as well as the study of the mechanism of their sensitizing action. Revealing of a compound providing significant chemosensitizing effect and characterized by a relatively low cost of synthesis would provide a low-cost solution for reduction of fungicidal treatments, while still providing sufficient protection even against fungicide-resistant strains of plant pathogens.