Biogeographical patterns of southern sequestrate Agaricomycetidae

TRUONG, CAMILLE; SMITH M.; KUHAR, FRANCISCO; NOUHRA E

San Juan

Congreso; International mycological congress; 2018

Truffle-like fungi form a heterogeneous group of diverse origin and they are common intemperate ectomycorrhizal (ECM) forests worldwide. The Nothofagaceae forests are restricted to thesouthern hemisphere and host a high diversity of fungi that are symbiotically associated with a relativelylow number of related tree species. This unusual richness includes genera where the transition tohypogeous 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 inmany lineages of sequestrate ECM fungi in southern temperate forests. Among the hypothetical drivingforces of this process are the adaptation to mycophagy, the closeness of the inoculum reservoir to theroots, and an increased resistance to drought or other climatic stressors. Since these factors are theresult of biogeographical processes (climate changes, distribution of ECM hosts, and mycophagousanimals), different selective pressures might explain differences in the sequestration process. Lineagespecific traits in fungi of restricted distribution are an alternative explanation to biogeographicalselective pressures leading to sequestration. Here we use newly generated sequences from Patagonianspecimens within the Agaricomycetidae to examine the phylogenetic component of sequestration andcompare it to biogeographic, climatic, and geologic influences. We discuss the influence of alternativehosts (e.g. Myrtaceae spp.) as well as hypotheses regarding putative historical host shifts and theirimplications on the evolution of sequestrate fungi