Diversity, climatic correlations, and biocontrol prospects of seed-borne fungal endophytes in Egyptian maize

Maize (Zea mays L.) is the world’s third most important cereal crop, valued for its roles in human food, animal feed, industrial products, and biofuels. Its seeds harbor diverse endophytic fungi that can affect seed quality, plant health, and resilience. Given the vertical transmission of seed microbiota, this study investigated the diversity of seed-borne fungal endophytes in Egyptian maize cultivars across 18 governorates and assessed their associations with regional climate. In addition, the study evaluated the antagonistic activity of native Trichoderma isolates as potential biocontrol agents against Fusarium verticillioides, a major seed-borne pathogen threatening maize production. A total of 34 endophytic fungal species from 23 genera were identified. Aspergillus niger, Penicillium spp., A. flavus, and F. verticillioides were the most prevalent, with A. niger occurring in 97.2% of sites and F. verticillioides in 89.6%. Relative abundances were highest for Penicillium spp. (20.08%), A. niger (18.15%), and F. verticillioides (14.93%). Diversity metrics varied regionally, with species richness ranging from 8 to 22 and Shannon diversity indices (H) from 1.02 to 2.46. Canonical correspondence analysis revealed that temperature, solar radiation, and humidity collectively explained 63.6% of fungal community variation. Trichoderma longibrachiatum (T14) demonstrated the strongest antagonistic effect, inhibiting F. verticillioides growth by 74.03% in vitro and exhibiting pronounced mycoparasitic features. This study highlights the dominance of a core group of seed-borne endophytes in Egyptian maize and underscores the significant role of climate in structuring fungal communities. However, as this study was based on single-season, culture-dependent data with limited molecular validation, further multi-seasonal and molecular-based investigations are needed to confirm these patterns and fully characterize the maize seed mycobiome. Notably, T. longibrachiatum demonstrated strong biocontrol potential against F. verticillioides, offering promise as a native, eco-friendly biocontrol agent for maize production systems in semi-arid environments.