Characterization and diversity of potential mycotoxin producing endophytic fungi isolated from maize husk leaves

Abstract

Maize (Zea mays L.) is an important staple food due to its good nutritional profile. Unfortunately, maize can be vulnerable to contamination by fungi, which are capable of producing mycotoxins that have an impact on human and animal health, crop productivity and lead to economic losses. In addition, the ubiquitous presence of mycotoxin-producing fungi in maize poses significant challenges to food safety and economic stability. Mycotoxins are toxic secondary metabolites produced by certain fungi, which, when ingested by humans or animals through contaminated maize products can lead to a variety of health issues. There is a shift of non-pathogenic microbes to pathogenic state due to unfavourable conditions arising. The aim of this study was to characterize and identify fungi that have the potential to produce mycotoxins isolated from maize husks. The study identified Fusaria sp., Aspergillus and Penicillium sp. as target species since they are often regarded as primary mycotoxin producing fungi, which often contaminates the maize plants. Ten (n=10) healthy (disease-free) and mature maize samples were obtained, and a total of 200 maize husk segments were utilized to isolate eighty-four (n=84) endophytic fungi. Preliminary identification was conducted using macroscopic and microscopic characteristics. Molecular processes using the Internal transcribed spacer region (ITS1 and ITS4) were used for PCR amplification as a confirmatory test. A total of 13 isolates were identified by macroscopic and microscopic characterization based on morphological features and their identification was confirmed using molecular techniques. Fusaria sp. were found to be predominant (46%), followed by Aspergillus sp. (39%) and Penicillium sp. (15%). The findings suggest a community of mycotoxin producing fungi inhibited within the maize husks. Under unfavourable conditions, these fungi might be the source of contamination and produce mycotoxins. In the face of changing environmental conditions and evolving fungal threats, our research serves as a valuable resource for understanding and addressing the challenges posed by mycotoxin contamination in maize. Effective strategies and interventions are essential to mitigate the impact of these fungi on food security, human health, and the global maize industry. Key words: Endophytes; fungi; food safety; maize; maize husks; mycotoxin; mycotoxin-producing fungi