Unlocking the Potential of Fungi and Their Metabolites for Sustainable Agriculture, Nutrition, and Health.

Fungi are often described as silent architects of ecosystems, yet their broader ecological and biotechnological significance remains underappreciated. This systematic review and meta-analysis synthesize current evidence on fungal diversity, ecological function, and metabolite production across agricultural, environmental, and extreme ecosystems. Following PRISMA 2020 guidelines, included studies were quantitatively and qualitatively analyzed to evaluate species richness, enzyme activity, metabolite yield, and plant growth–promoting effects. The pooled analyses revealed substantial ecological variation in fungal diversity, with nutrient-rich systems such as compost and agricultural soils consistently demonstrating higher species richness and functional outputs than extreme habitats. Filamentous fungi, particularly Aspergillus and Trichoderma, showed significantly greater extracellular enzyme activity, while edible and medicinal fungi were enriched in bioactive polysaccharides and antioxidant metabolites. A strong positive correlation (r = 0.72, p < 0.001) was observed between species richness and metabolite yield, suggesting that biodiversity directly influences functional potential. Although heterogeneity was present due to methodological and ecological variability, random-effects modeling confirmed the robustness of pooled estimates. Evidence also supports fungal applications in biofertilization, heavy-metal mitigation, functional food development, enzyme production, and biopharmaceutical discovery. Collectively, the findings position fungi not merely as decomposers or fermentation agents, but as multifunctional biological resources central to sustainable agriculture, nutrition, and biotechnology. Preserving fungal biodiversity and integrating it into circular bioeconomy frameworks may be essential for addressing global food security and environmental resilience challenges.