Biocontrol activity of the marine yeast Debaryomyces hansenii against phytopathogenic fungi and its ability to inhibit mycotoxins production in maize grain (Zea mays L.)

•In vitro tests D. hansenii significant decreases the mycelial growth of four maize postharvest pathogens.•Presence of D. hansenii reduced the production of fumonisins of F. subglutinans in 59.8% in vivo.•First time that marine yeast is used to the mold control in maize grain.

Debaryomyces hansenii is an antagonistic yeast that has been shown high effectiveness against different phytopathogenic fungi in diverse habitats. Both, the antagonistic activity of D. hansenii BCS003 and its mechanism against four pathogenic fungi (Mucor circinelloides, Aspergillus sp., Fusarium proliferatum and Fusarium subglutinans) in maize grains (Zea mays L.) were evaluated. Results indicated an almost entirely decrease (97.2–98.3%) of mycelial growth in a radial inhibition assay against four strains of pathogenic fungi by the D. hansenii action. In diffusible and volatile compounds as well cell-free supernatants in vitro assays D. hansenii showed significant inhibitory activity (p < 0.05) against Aspergillus sp., F. proliferatum and F. subglutinans. The four isolated fungi were used to infect maize grains and results showed a partial inhibition of the mycelial growth and a 24 h delay in the disease appearance when compared to control (not D. hansenii treated maize grain). Moreover, the application of D. hansenii reduced the production of F. subglutinans fumonisins by 59.8% after seven days of co-incubation without affecting the chemical and mineral composition of maize grain. According to these results, D. hansenii BCS003 could be considered a potential biocontrol agent against toxigenic molds in maize grains, probably due to the synergistic effects of the factors such as the competition for nutrients and space, as well as the production of extracellular soluble and volatile compounds. The potential of marine D. hansenii as biocontrol agent merits further research to improve its efficacy.

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