Growth Dynamics, Sporulation and Stability of Aflatoxin Production in Aspergillus flavus Strains From Preharvest Maize in Argentina

Abstract

Non-aflatoxigenic Aspergillus flavus strains have emerged as promising biocontrol agents to reduce aflatoxin contamination in maize crops. This study aimed to evaluate the growth dynamics, sporulation capacity and phenotypic stability of local non-aflatoxigenic A. flavus strains from Argentina compared to aflatoxigenic strains. Eighteen non-aflatoxigenic strains, isolated from maize ears grown in Argentina's central agricultural region, were assessed for growth and spore production at various temperatures, with the results indicating superior growth and sporulation under optimal conditions (30°C). The phenotypic stability of these strains was tested by conducting 20 consecutive subcultures, confirming the retention of their non-aflatoxigenic character. The local non-aflatoxigenic strains lack the nucleotide 591 polymorphism in the pksA gene, indicating that their inability to produce aflatoxins is not due to this mutation. These strains demonstrated the ability to survive and grow under high-temperature conditions, making them suitable candidates for biocontrol applications in regions with variable climates and significant thermal amplitudes. The findings support the potential of these local non-aflatoxigenic strains as effective biocontrol agents to mitigate aflatoxin contamination in maize production systems in Argentina.