Evidence of an Indigenous Microbiota (Yeast) in the Dry Valleys of Antarctica

Abstract

SUMMARY: Soil samples from sites in the Dry Valleys of South Victoria Land, Antarctica, similar to some sites previously considered abiotic, contained a variety of microbes. The fungi recovered included Tilletiopsis washingtonensis, Sporobolomyces holsaticus, Sp. roseus (all previously unreported from Antarctica), Cryptococcus laurentii var. laurentii and Cr. vishniacii, as well as some unremarkable filamentous fungi imperfecti. Cryptococcus vishniacii occurs only in these soils, has a distribution suggesting indigenous origin and shows appropriate psychrophilic character and energy requirements for life in this highly stressed environment. Populations of Cr. vishniacii cloned and grown at 4 °C are heterogeneous in temperature response, some cells being capable of growth at 20 °C or 23 °C with loss of the ability to assimilate succinate or citrate. Cryptococcus vishniacii and endolithic cyano-bacteria could constitute a minimal community in Dry Valley soils.