Fungal endophytes are symbiotic microorganisms that establish strong relationships inside plant tissues, providing potential advantages, especially in grasses, by enhancing tolerance to both abiotic and biotic stresses. This review investigates the molecular mechanisms through which fungal endophytes mediate stress tolerance, targeting host–pathogen interactions. By modulating pathogen-associated molecular patterns (PAMPs), damage-associated molecular patterns (DAMPs), and effector proteins, fungal endophytes may contribute to priming the plant’s immune system, enhancing its resistance to pathogen invasion. Moreover, endophyte colonization regulates core processes such as osmotic regulation, reactive oxygen species (ROS) detoxification, and secondary metabolite biosynthesis that enable plants to tolerate environmental stresses like drought, heat, and salinity. The review highlights the impact of endophytes on immune priming, systemic acquired resistance (SAR), and the regulation of non-coding RNAs that regulate host gene networks associated with stress tolerance. Furthermore, the integration of advanced multi-omics techniques genomics, transcriptomics, proteomics, metabolomics, and fluxomics has revealed emerging insights into the genetic and metabolic pathways driving these symbiotic associations. However, grass-specific molecular datasets remain limited, and the consistency of endophyte-mediated tolerance across host species and environmental conditions is not yet fully resolved. Fungal endophytes increase grass stress resilience through coordinated pathogen recognition, RNA regulation, and metabolic reprogramming while AI-assisted multi-omics approaches are emerging as tools for identifying candidate regulatory networks, although empirical validation in grass–endophyte systems remains limited. Together, these advances highlight the potential for climate-smart and sustainable crop improvement. Future research integrating functional genomics, field validation, and biosafety assessment will be essential for translating endophyte-based strategies into reliable agricultural applications.
Ahmad et al. (2026) studied this question.