LAUSR

Abstract An ultraperformance liquid chromatography system was used to establish the presence of seven aromatic carboxylic acids, known as antimicrobial substances, in root exudates of barley colonized by the phytopathogenic fungus Fusarium culmorum and the antagonistic bacterium Pseudomonas fluorescens . It was established that barley produced fewer antimicrobial components in exudates in response to the colonization of P. fluorescens than after colonization by F. culmorum . All aromatic carboxylic acids inhibited the growth of F. culmorum , but only two of them inhibited the growth of P. fluorescens and only at the highest concentration. The obtained data demonstrate the ability of the plant to create favorable conditions for the development of beneficial rhizobacteria and to create unfavorable conditions for the growth of the phytopathogenic fungus via the composition of root exudates. In the future, it will be possible to select varieties of grain crops with a specific composition of antimicrobial components in root exudates.