Abstract
<title>Abstract</title> <p> Orchid mycorrhizal (ORM) fungi are essential for seed germination and plant development, yet their functional diversity remains poorly understood. In this study, we isolated and characterized rhizoctonia-like fungi from roots of the terrestrial generalist orchid <italic>Anacamptis morio</italic> collected across nine populations in Northern Italy. Sequencing and phylogenetic analyses of the ribosomal Internal Transcribed Spacer (ITS) identified isolates as belonging to the families Ceratobasidiaceae and Tulasnellaceae. A subset of isolates was functionally characterized for growth responses under different temperature regimes simulating current and future climate scenarios, for metabolic profiles using BIOLOG® carbon utilization assays and for the ability to induce symbiotic seed germination. Isolates exhibited marked functional variability across all tested traits. Growth responses to increasing temperature were strain-specific, suggesting differential resilience to climate change. Metabolic profiling revealed distinct substrate utilization strategies among isolates. Symbiotic performance also varied considerably, with some isolates promoting advanced protocorm and plantlet development and others showing limited or no germination-promoting capacity. These findings demonstrate functional heterogeneity of ORM fungi associated with adult plants of <italic>A. morio</italic> , and suggest that a portfolio of different symbionts may contribute to orchid performance under different developmental and/or environmental conditions. </p>