Aadab Akhtar

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.

Fungal endophytes are microorganisms that inhabit plant tissues without causing disease and emerge as critical mediators of plant stress tolerance, nutrient acquisition, and ecosystem resilience under diverse climate change scenarios. Their unique position within the host allows them to modulate physiological responses more closely than external microbiota. This review explores how endophytic fungi contribute to plant adaptation under climate-induced stresses such as heat, salinity, drought, pollution, and nutrient limitation, with a focus on molecular crosstalk, functional trait modules, and metabolic trade-offs. Key findings emphasize multilayered signaling systems, including MAMP/DAMP recognition, phytohormone regulation, immune tuning, ROS dynamics, and effector deployment, while emerging mechanisms such as cross-kingdom RNA and extracellular vesicle (EV)-mediated exchange are discussed as promising but currently limited in empirical validation within many endophytic systems. Endophytes also enhance nutrient exchange through conditional carbon-for-benefit trade and may shape rhizosphere microbiota and soil activities through plant-mediated inputs. Integrative multi-omics approaches provide predominantly correlational insights into the mechanistic basis of these effects, linking molecular function to ecosystem and community outcomes. These insights have potential applications in climate-resilient agriculture, phytoremediation, and ecosystem restoration; however, their large-scale implementation requires further field-based validation and context-specific assessment. Future priorities should focus on trait-based selection, ecological modeling, and biosafety evaluation to translate microbial functions into reliable field-level strategies that support sustainable crop performance under accelerating environmental stress.