Light and scanning electron microscopic characterization of aflatoxins producing Aspergillus flavus in the maize crop

Maize (Zea mays L.) is considered as one of the main cereals, used as a source of food, forage, and processed products. The loss of maize productivity is reported due to effect on roots, stalks, ears, and kernels mainly caused by many fungi. Among these fungal pathogens of maize, Aspergillus flavus (A. flavus) are the most prevalent that produces highly toxigenic aflatoxins that are highly carcinogenic to the consumers. The present study is confined to isolate and characterize the A. flavus from maize seeds for accurate identification that can be helpful for determination and management of aflatoxins in maize crop. Eighty stored seed samples of maize were collected from warehouses where seeds are stored for food and feeding purposes. For the isolation of A. flavus, Potato Dextrose Agar was used. Isolated fungi were identified macro and microscopically using light microscope and scanning electron microscope. A total of 212 Aspergillus isolates were identified based on macro-morphological and micro-morphological characteristics. The results showed that A. flavus colonies were granular, flat with yellow-green to deep yellow-green colony color having a white border and compact, spherical spore heads. Rapid rate of growth was observed maturing in about 3-5 days. In microscopic features, A. flavus have apically swollen conidiophores with various conidia bearing cells in long and dry chains. Spherical conidial heads were split into several columns ranging 300-400 mu m in diameter. This will be helpful for farmers, researchers and traders in future for correct identification of sources of aflatoxins.

Automated summary

This study successfully isolated and characterized A. flavus from maize seeds, which will be beneficial for future proper identification of aflatoxin sources by farmers, researchers, and traders.