Survey of the Trunk Wood Mycobiome of an Ancient <em>Tilia</em> × <em>europaea</em> L.

The genus Tilia (Malvaceae) comprises long-lived broadleaf trees of considerable ecological, cultural, and historical importance in temperate Europe and Asia. Among these, Tilia × europaea L. is a key native species in Central and Northern Europe, with individuals documented to live for several centuries. While the external and soil-associated microbiomes of linden have been studied, the internal fungal communities inhabiting ancient trees remain poorly understood. Wood-inhabiting fungi (the wood mycobiome) include endophytes, saprotrophs, and potential pathogens that can strongly influence host vitality and ecosystem processes. Advances in high-throughput amplicon sequencing (HTAS) now provide unprecedented opportunities to characterize these hidden communities. In this study, we investigated the trunk wood mycobiome of an ancient Tilia × europaea L. individual using a culture-independent HTAS approach. The results reveal a diverse fungal assemblage, including taxa like Arthinium or Phialemonium not previously reported from living linden wood, and highlight potential implications for tree health and longevity. This work provides a first baseline characterization of the internal mycobiome of ancient Tilia trees and contributes to broader efforts to conserve their biological and cultural value.