Abstract: Plant-associated symbiotic mycobiomes play critical roles in crop adaptation to harsh environments. However, knowledge of wheat mycobiomes in alpine ecosystems remains limited. This study investigated the diversity, composition, and functional adaptations of symbiotic fungi associated with the wheats cultivated in alpine areas on the Pamir Plateau and adjacent lowland regions. Our results revealed distinct fungal community structures between the alpine and low-land habitats and across different plant compartments (stems, roots, and rhizosphere), with higher fungal diversity observed in roots and rhizospheres compared to stems. Taxonomically, Eurotiomycetes predominated in alpine samples, while Tremellomycetes were more abundant in lowland areas. Fungal co-occurrence network analysis exhibited a higher proportion of positive associations among fungal taxa in alpine environments, supporting the stress gradient hypothesis that environmental stresses enhance mutualistic relationships. Functional analyses demonstrated that saprotrophic fungi dominated both regions; however, alpine fungi were more inclined toward endophytic and saprotrophic strategies, whereas pathogenic and parasitic fungi were prevalent in lowlands. These distinctions suggested that the harsh environmental conditions in alpine regions may drive plant-associated fungi toward biotrophic strategies as adaptive responses. Our findings highlight how environmental factors shape symbiotic fungal community composition and function, offering insights into utilizing these microbial communities for sustainable agriculture in challenging alpine conditions.

Key words: wheat, alpine environment, symbiotic mycobiome, fungal community, trophic strategies, co-occurrence networks