The Distribution and Identity of Edaphic Fungi in the McMurdo Dry Valleys

Abstract

Contrary to earlier assumptions, molecular evidence has demonstrated the presence of diverse and localized soil bacterial communities in the McMurdo Dry Valleys of Antarctica. Meanwhile, it remains unclear whether fungal signals so far detected in Dry Valley soils using both culture-based and molecular techniques represent adapted and ecologically active biomass or spores transported by wind. Through a systematic and quantitative molecular survey, we identified significant heterogeneities in soil fungal communities across the Dry Valleys that robustly correlate with heterogeneities in soil physicochemical properties. Community fingerprinting analysis and 454 pyrosequencing of the fungal ribosomal intergenic spacer region revealed different levels of heterogeneity in fungal diversity within individual Dry Valleys and a surprising abundance of Chytridiomycota species, whereas previous studies suggested that Dry Valley soils were dominated by Ascomycota and Basidiomycota. Critically, we identified significant differences in fungal community composition and structure of adjacent sites with no obvious barrier to aeolian transport between them. These findings suggest that edaphic fungi of the Antarctic Dry Valleys are adapted to local environments and represent an ecologically relevant (and possibly important) heterotrophic component of the ecosystem.

Comparative activity and functional ecology of permafrost soils and lithic niches in a hyper‐arid polar desert

“…Similar to other Dry Valleys , Ascomycota and Basidiomycota were the dominant edaphic and lithobiontic fungal phyla, but the phylum Chytridiomycota , abundant in Dry Valley active layer soils (Dreesens et al ., ), was absent in the University Valley permafrost soils and was negligible in the cryptoendolith community (< 0.001%). The fungi to bacteria ratio was low in the permafrost soil, as has been observed in the Dry Valleys before, likely due to the low water activity, low C:N ratios, and more extreme conditions that restrict fungal growth and dispersal in high elevation inland soils, while still permitting bacterial survival (Dreesens et al ., ). Though more abundant among the cryptoendolith, similar Ascomycota fungi were found in both habitats and consisted mainly of Eurotiomycetes , Sordariomycetes and Dothideomycetes .…”

ANaganishiain high places: functioning populations or dormant cells from the atmosphere?

“…The relative abundance of Naganishia species in microbial communities of the Dry Valleys of Antarctica is less clear because most studies have been based on culture-dependent approaches focusing solely on specific species (Vishniac and Hempfling 1979; Vishniac 1985a, 1985b, 2006). Two recent culture-independent studies of microbial communities indicated that Naganishia are rare in many Dry Valley soils (Fell et al 2006), but are quite common in several higher elevation sites (Dreesens et al 2014). It is possible that the source for the Naganishia species found in Antarctica is the continuous dispersal of dust and particles from the Southern Andes via meandering Rossby waves in the troposphere (Madden 1979).…”

Comparison of the oxidative stress response of two Antarctic fungi to different growth temperatures

“…The new sequencing technologies helped to elucidate the fungal diversity in Antarctica through identifying uncultivable isolates. The molecular methods confirmed domination of Ascomycota and Basidiomycota, especially in Dry Valley soils (Arenz et al 2006;Cantrell et al 2011;Dreesens et al 2014;Cox et al 2016). The analysis of environmental DNA and RNA (cDNA) for inland Dry Valleys soil showed that approximately half of fungal phylotypes recovered from the RNA-derived library did not affiliate phylogenetically with any known fungus (Rao et al 2012).…”