Invited Talk Title: Biogeographical patterns of southern sequestrate Agaricomycetidae.

CAMILLE TRUONG; EDUARDO NOUHRA; FRANCISCO KUHAR; SMITH, MATTHEW E.

San Juan

Congreso; 11th International Mycological Congress; 2018

International Mycological Association

Truffle-like fungi form a heterogeneous group of diverse origin and they are common in temperate ectomycorrhizal (ECM) forests worldwide. The Nothofagaceae forests are restricted to the southern hemisphere and host a high diversity of fungi that are symbiotically associated with a relatively low number of related tree species. This unusual richness includes genera where the transition to hypogeous or subhypogeous forms is known to have occurred many times in their evolutionary history. Different degrees of hymenium exposure, stipe reduction, and loss of forcible spore discharge occur in many lineages of sequestrate ECM fungi in southern temperate forests. Among the hypothetical driving forces of this process are the adaptation to mycophagy, the closeness of the inoculum reservoir to the roots, and an increased resistance to drought or other climatic stressors. Since these factors are the result of biogeographical processes (climate changes, distribution of ECM hosts, and mycophagous animals), different selective pressures might explain differences in the sequestration process. Lineage specific traits in fungi of restricted distribution are an alternative explanation to biogeographical selective pressures leading to sequestration. Here we use newly generated sequences from Patagonian specimens within the Agaricomycetidae to examine the phylogenetic component of sequestration and compare it to biogeographic, climatic, and geologic influences. We discuss the influence of alternative hosts (e.g. Myrtaceae spp.) as well as hypotheses regarding putative historical host shifts and their implications on the evolution of sequestrate fungi.