Solving the ecological puzzle of mycorrhizal associations using data from annotated collections and environmental samples – an example of saddle fungi

Summary The relation between ecological and genetic divergence of Helvella species (saddle fungi) has been perplexing. While a few species have been clearly demonstrated to be ectomycorrhizal fungi, ecological roles of many other species have been controversial, alternately considered as either saprotrophic or mycorrhizal. We applied SAT é to build an inclusive deoxyribonucleic acid sequence alignment for the internal transcribed spacers ( ITS ) of annotated H elvella species and related environmental sequences. Phylogenetic informativeness of ITS and its regions were assessed using P hy D esign . Mycorrhizal lineages present a diversity of ecology, host type and geographic distribution. In two H elvella clades, no H elvella   ITS sequences were recovered from root tips. Inclusion of environmental sequences in the ITS phylogeny from these sequences has the potential to link these data and reveal H elvella ecology. This study can serve as a model for revealing the diversity of relationships between unculturable fungi and their potential plant hosts. How non‐mycorrhizal life styles within H elvella evolved will require expanded metagenomic investigation of soil and other environmental samples along with study of H elvella genomes.