Validation and Ecological Niche Investigation of a New Fungal Intraspecific Competitor as a Biocontrol Agent for the Sustainable Containment of Aflatoxins on Maize Fields

Abstract

Crop yield and plant products quality are directly or indirectly affected by climate alterations. Adverse climatic conditions often promote the occurrence of different abiotic stresses, which can reduce or enhance the susceptibility to pests or pathogens. Aflatoxin producing fungi, in particular, whose diffusion and deleterious consequences on cereals commodities have been demonstrated to highly depend on the temperature and humidity conditions that threaten increasingly larger areas. Biological methods using intraspecific competitors to prevent fungal development and/or toxin production at the pre-harvest level are particularly promising, even if their efficacy could be affected by the ecological interaction within the resident microbial population. A previously characterized Aspergillus flavus atoxigenic strain was applied in two maize fields to validate its effectiveness as a biocontrol agent against aflatoxin contamination. At one month post-application, at the harvest stage, its persistence within the A. flavus population colonizing the maize kernels in the treated area was assessed, and its efficacy was compared in vitro with a representation of the isolated atoxigenic population. Results proved that our fungal competitor contained the aflatoxin level on maize grains as successfully as a traditional chemical strategy, even if representing less than 30% of the atoxigenic strains re-isolated, and achieved the best performance (in terms of bio-competitive potential) concerning endogenous atoxigenic isolates.

Exploring the Biocontrol Capability of Non-Mycotoxigenic Strains of Penicillium expansum

“…Several commercially available products have been developed [ 28 , 29 , 30 , 31 ]. Biocontrol remedies generated worldwide using non-mycotoxigenic strains of A. flavus have a common characteristic: they use native A. flavus strains chosen from the specific region where they are intended to be applied [ 32 ]. The biocontrol potential of natural non-ochratoxigenic strains of Aspergillus carbonarius has also been recently described [ 33 , 34 ].…”