Natural compounds derived from Brassicaceae plants as an alternative to synthetic fungicides and their influence on soil fungus diversity.

Background: The study aimed to develop a new formulation based on active substances of natural origin to protect plant seedlings against fungal pathogens, and to evaluate the effect of this formulation on fungal communities in arable soil.

Results: Coating seeds of common crop plants with a p-coumaric acid (p-CA)-based preparation resulted in a significant reduction in the growth of most of the tested pathogens. When applied to soil, both the p-CA-based formulation and Porter 250 EC had a similar overall effect on soil fungal communities and significantly altered the structure of fungal communities at all of the times examined. Shifts in the fungal community composition concerned less than 2% of the total number of amplicon sequence variants (ASVs). The strongest impact of the formulations on soil microbiota was recorded at the fourth week of treatment. Two ASVs assigned to Botrytis and Chromelosporium, known as plant pathogens, and an unidentified ASV from Diversisporales encompassing the arbuscular mycorrhizal fungi (AMF), were significantly depleted in soil samples treated with p-CA in comparison with Porter 250 EC.

Conclusion: The p-CA-based preparation has the potential to be used as an alternative to synthetic fungicides. It shows a similar effect to Porter 250 EC on the organization of soil communities, determining changes in the character of the communities of fungi in general, at any given time. Moreover, p-CA caused a reduction in ASVs belonging to Botrytis and Chromelosporium (plant pathogens) and ASVs of Diversisporales (containing arbuscular mycorrhizal fungi) in comparison with the commercial compound that was analyzed. © 2022 Society of Chemical Industry.