A thin ice layer segregates two distinct fungal communities in Antarctic brines from Tarn Flat (Northern Victoria Land)

This is the accepted manuscript of the paper: Borruso L., Sannino C., Selbmann L., Battistel D., Zucconi L., Azzaro M., Turchetti B., Buzzini P., Guglielmin M., (2018). A thin ice layer segregates two distinct fungal communities in Antarctic brines from Tarn Flat (Northern Victoria Land). Scientific Reports 8: 6582 | DOI:10.1038/s41598-018-25079-3

Abstract

Brines are hypersaline solutions which have been found within the Antarctic permafrost from the Tarn
Flat area (Northern Victoria Land). Here, an investigation on the possible presence and diversity of
fungal life within those peculiar ecosystems has been carried out for the first time. Brines samples were
collected at 4- and 5-meter depths (TF1 and TF2, respectively), from two brines separated by a thin ice
layer. The samples were analyzed via Illumina MiSeq targeting the ITS region specific for both yeasts
and filamentous fungi. An unexpected high alpha diversity was found. Beta diversity analysis revealed
that the two brines were inhabited by two phylogenetically diverse fungal communities (Unifrac value:
0.56, p value < 0.01; Martin’s P-test p-value < 0.001) characterized by several specialist taxa. The most
abundant fungal genera were Candida sp., Leucosporidium sp., Naganishia sp. and Sporobolomyces sp.
in TF1, and Leucosporidium sp., Malassezia sp., Naganishia sp. and Sporobolomyces sp. in TF2. A few
hypotheses on such differentiation have been done: i) the different chemical and physical composition
of the brines; ii) the presence in situ of a thin layer of ice, acting as a physical barrier; and iii) the diverse
geological origin of the brines.