Occurrence of arbuscular mycorrhizal fungi on King George Island, South Shetland Islands, Antarctica

Marisângela V Barbosa,Elismara A Pereira,Marco A.C Carneiro,Juliano C Cury

doi:10.1590/0001-3765201720170119

Abstract

Arbuscular mycorrhizal fungi make up an important ecological niche in ecosystems, and knowledge of their diversity in extreme environments is still incipient. The objective of this work was to evaluate the density and diversity of arbuscular mycorrhizal fungi in the soil of King George Island in the South Shetland Islands archipelago, Antarctica. For that, soil and roots of Deschampsia antarctica were collected at the brazilian research station in Antarctica. The spore density, species diversity and mycorrhizal colonization in the roots were evaluated. There was a low density of spores (27.4 ± 17.7) and root mycorrhizal colonization (6 ± 5.1%), which did not present statistical difference. Four species of arbuscular mycorrhizal fungi were identified, distributed in two genera: three species of the genus Glomus (Glomus sp1, Glomus sp2 and Glomus sp3) and one of the genus Acaulospora, which was identified at species level (Acaulospora mellea). Greater soil diversity was verified with pH 5.9 and phosphorus concentration of 111 mg dm-3, occurring two species of genus Glomus and A. mellea. Based on literature data, this may be the first record of this species of Acaulospora mellea in Antarctic soils, colonizing D. antarctica plants.

Highlights

Antarctica is the largest ice reserve in the world, with an area of 14 million km2 and about 95% of the continent covered by ice that concentratesThe Antarctic continent presents extreme edaphoclimatic limitations, which regulate the biodiversity of plants and organisms in the soil
The limiting conditions in this region condition a limited flora, composed almost exclusively of lichens, bryophytes and two species of vascular plants of angiosperms, one Caryophyllaceae Colobanthus quitensis (Kunth) Bartl. and one Poaceae Deschampsia antarctica Desv. which predominates on the surfaces of the large rocky blocks (Lewis-Smith and Poncet 1985, Gonçalves et al 2008)
The present study reinforces this assertion by showing the existence of this fungus group in soil samples and roots of the D. antarctica species on King George Island (Table I and Figure 1)

Summary

Introduction

The Antarctic continent presents extreme edaphoclimatic limitations, which regulate the biodiversity of plants and organisms in the soil. In the evolutionary sequence of eukaryotes, the group of microorganisms that form the most intimate and durable symbiosis in nature are arbuscular mycorrhizal fungi (AMFs) (Allen 1996, Smith and Read 2008). This symbiosis is reported in fossil evidence, which shows the presence of AMF structures associated with Notophytum krauselii in Antarctic soil as early as the Triassic period of approximately 400 million years (Harper et al 2015)

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