Endolithic Fungal Species Markers for Harshest Conditions in the McMurdo Dry Valleys, Antarctica.

Claudia Coleine,Laura Selbmann,Silvano Onofri,Laura Zucconi,Jason E Stajich,Nuttapon Pombubpa

doi:10.3390/life10020013

Claudia Coleine, Laura Selbmann + Show 4 more

Open Access

https://doi.org/10.3390/life10020013

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Journal: Life	Publication Date: Feb 6, 2020
Citations: 14	License type: CC BY 4.0

Affiliation: Tuscia University, University of California, Riverside

Abstract

The microbial communities that inhabit lithic niches inside sandstone in the Antarctic McMurdo Dry Valleys of life’s limits on Earth. The cryptoendolithic communities survive in these ice-free areas that have the lowest temperatures on Earth coupled with strong thermal fluctuations, extreme aridity, oligotrophy and high levels of solar and UV radiation. In this study, based on DNA metabarcoding, targeting the fungal Internal Transcribed Spacer region 1 (ITS1) and multivariate statistical analyses, we supply the first comprehensive overview onto the fungal diversity and composition of these communities sampled over a broad geographic area of the Antarctic hyper-arid cold desert. Six locations with surfaces that experience variable sun exposure were sampled to compare communities from a common area across a gradient of environmental pressure. The Operational Taxonomic Units (OTUs) identified were primarily members of the Ascomycota phylum, comprised mostly of the Lecanoromycetes and Dothideomycetes classes. The fungal species Friedmanniomyces endolithicus, endemic to Antarctica, was found to be a marker species to the harshest conditions occurring in the shady, south exposed rock surfaces. Analysis of community composition showed that sun exposure was an environmental property that explained community diversity and structured endolithic colonization.

Highlights

The McMurdo Dry Valleys in Antarctica cover about 4000 square km; free of snow and ice for the30% of the surface, they represent the largest ice-free region of the continent
Dry Valley, the largest ice-free area in Antarctica, sampling the main accessible sandstone outcrops and McMurdo Dry Valley, the largest ice-free area in Antarctica, sampling the main accessible sandstone considering opposite sun-exposed surfaces to test the effect of sunlight on fungal diversity
Using Internal Transcribed Spacer region 1 (ITS1) metabarcoding, we identified Lecanoromycetes, Tremellomycetes, Dothideomycetes diversity

Summary

Introduction

The McMurdo Dry Valleys in Antarctica cover about 4000 square km; free of snow and ice for the30% of the surface, they represent the largest ice-free region of the continent. The landscape includes mountain ranges, nunataks, glaciers, ice-free valleys, frozen lakes, ponds, meltwater streams, arid soils and permafrost, sand dunes, and interconnected water systems. This region represents a nearly pristine environment, largely undisturbed and uncontaminated by humans, while hosts unusual microhabitats and biological communities and unique geological features and minerals. Due to the unique geological and biological characteristics, the McMurdo Dry Valleys, as a whole, are designated as an ASMA (Antarctic Specially Managed Area) to assist planning and coordination of activities to ensure the long-term protection of this unique environment and to safeguard its values for scientific research, education, and minimize environmental impacts [1]. ASPA (Antarctic Specially Protected Areas); each ASPA has its own management plan and require specific permits for entry.

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