Ascomycetous Endophytic Fungi Drive Root Fungal Community Assembly in Wheat Under Moderate Drought

Drought stress severely limits wheat growth, development and yield. Endophytic fungi play a crucial role in plant growth and drought resistance. In agricultural production, they hold significant application potential as biocontrol agents capable of mitigating drought-induced damage. However, the mechanisms underlying changes in endophytic fungal community structure under drought stress remain unclear. Our study employed amplicon sequencing to investigate the structure of endophytic fungal communities in wheat roots under different water treatments, comparing structural and functional changes between different treatments. Results revealed that drought stress led to the greatest accumulation of relative abundance in the phylum Ascomycota (86.4%). At the genus level, <i>Stachybotrys</i> (increase 994.2%), <i>Fusarium</i> (increase 94.6%) and <i>Aspergillus</i> (increase 295.6%) showed the most significant increases in relative abundance. Co-occurrence network and Sankey diagram analysis revealed that wheat roots formed a drought-specific endophytic fungal community centered around <i>Stachybotrys</i>, <i>Fusarium</i> and <i>Aspergillus</i>, which indirectly enhanced crop drought tolerance. Our findings provide a theoretical foundation for future agricultural strategies to improve crop drought resistance through precise regulation of microbial communities.