Agricultural soils as a potential reservoir of mycotoxigenic Fusarium spp. in northwest Spain

Abstract

Fusarium species, which are widely distributed across agricultural ecosystems worldwide, are among the most economically harmful phytopathogens. They can colonize a broad range of agri-food crops, causing plant diseases and the accumulation of mycotoxins in edible plant tissues. Fusarium species produce a variety of secondary metabolites, posing toxicological risks to human and animal health. A total of 119 Fusarium strains isolated from agricultural soils in northwestern Iberian Peninsula were molecularly identified at the species level, and their capability to produce 17 mycotoxins was evaluated in vitro using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). A high Fusarium biodiversity was observed, as 15 Fusarium species in eight species complexes were detected, some of them not extensively described in Spanish soils, including Fusarium algeriense , Fusarium brachygibbosum , Fusarium clavum , and Fusarium flagelliforme . Each Fusarium strain showed a specific mycotoxin profile with varying concentrations. Beauvericin and enniatins were the most prevalent at very high levels, and for a number of species, production has not been previously reported. Trichothecenes and fumonisins were less frequently detected than expected from previous reports. The multi-mycotoxin profiles were shaped by species identity, the only significant factor, rather than by soil environmental characteristics. These findings highlight soil as a reservoir of phytopathogenic and mycotoxigenic Fusarium spp., contribute to characterizing their toxigenic profiles, and emphasize the need to investigate emerging mycotoxins.