First reported aflatoxigenic isolates of Aspergillus flavus in agroforestry systems in Buenaventura, Valle del Cauca-Colombia

Abstract

Aspergillus flavus is a common fungus in agricultural and agroforestry systems, and its presence can pose several risks, especially in agroforestry systems. Aflatoxin contamination of staple crops is a major problem in the Pacific region of Colombia. This study aimed to analyze the morphological, molecular and aflatoxigenic characteristics of Aspergillus species found in agroforestry systems in the Buenaventura region of Colombia. The study employed first- and second-degree logarithmic models to analyse fungal growth and its rate of variation over time. Genomic DNA was extracted from individual spore cultures sown on Potato Dextrose Agar (PDA). The DNA was amplified by polymerase chain reaction (PCR) using a reaction mixture consisting of 12.5 µL of PCR Master Mix 2X, 1 µL of each primer and 2 µL of genomic DNA. PCR was used to detect aflatoxins by amplifying the AflS gene using AflS-F and AflS-R. Quantitative analysis was performed using the direct competitive ELISA (CD-ELISA) method. This study presents the initial sequences of Aspergillus flavus linked to agroforestry systems in Buenaventura, Valle del Cauca-Colombia. The sequences for ITS and BenA were deposited in the NCBI GenBank database under the codes PP379903/PP379904 and PP565787/PP565788, respectively. Isolates PP565787 and PP565788 were identified as aflatoxigenic with concentrations of 5.7 ppb and 3.8 ppb, respectively. This article proposes the use of non-toxigenic strains of A flavus and other beneficial microorganisms as biocontrollers through competition, as well as the use of agricultural lime as a sustainable option in agroforestry systems in regions with limited technology.