Molecular Characterization of Tamarindus indica Associated with Fungal Diversity and Detection of Aflatoxin Biosynthesiser Genes

Background: The tamarind tree (Tamarindus indica), valued for its nutritional and economic importance, faces significant food safety challenges due to fungal contamination and mycotoxin production. This study aims to characterize the toxigenic fungal flora of tamarind pulp to provide crucial information for developing improved management practices to ensure food safety and protect public health in the region. Methods: Tamarind samples (n=180) collected from different locations were analyzed for pH, Titratable Acidity, and Moisture Content. Fungal diversity was assessed with emphasis on the molecular identification of Aspergillus species. The ammonia vapor test was used to detect aflatoxigenic isolates, while the presence of key aflatoxin biosynthesis genes (aflD, aflM, aflO, aflP, aflQ, and aflR) was investigated by Polymerase Chain Reaction amplification. Restriction Fragment Length Polymorphism analysis was applied to group isolates. The data were analyzed using the Kruskal-Wallis test in R software (version 4.4.3; R Foundation for Statistical Computing) to assess differences between groups. Statistical significance was determined at p<0.05. Results: Tamarind was highly acidic (pH<3) with low Titratable Acidity (4-5%) and low water content (14-20%), which improves storage stability. Fungal analysis identified five species, namely Monascus pilosus, Aspergillus melleus, Aspergillus aflatoxiformans, Aspergillus niger, and Aspergillus costaricensis (the most frequently isolated species). Molecular analysis revealed amplification of four distinct fungal profiles, highlighting the usefulness of Restriction Fragment Length Polymorphisms for grouping isolates. However, closely related species such as A. niger and A. costaricensis were difficult to distinguish. Amplification of the aflD, aflM, aflO, aflP, aflQ, and aflR genes in A. aflatoxiformans isolates confirmed their ability to synthesise aflatoxins. Conclusion: This study highlighted the vulnerability of tamarind to contamination by aflatoxin-producing fungi. Monitoring mycotoxin levels and improving storage practices are essential to ensure tamarind safety and protect consumer health.