Cyanobacteria in Hypolithic Horizons of Soils in the Larsemann Hills, East Antarctica

Abstract

The research is devoted to the analysis of biodiversity of Antarctic soil cyanobacteria in hypolithic organo-accumulative horizons of the Larsemann Hills (East Antarctica). Studying of fouling glasses by the methods of light and confocal microscopy, as well as fluorescent in situ hybridization, has shown that filamentous forms predominate among cyanobacteria in the upper layers of Antarctic hypolithic microbial communities. To clarify the taxonomic status, strains of the genera Nostoc, Halotia, Leptolyngbya, Plectolyngbya, Phormidesmis, as well as some new and previously undescribed representatives of Antarctic cyanobacteria were isolated from corresponding soil samples. The strains of the unique collection of soil cyanobacteria that we formed for the first time were described according to modern methods of polyphasic taxonomy based on analysis of the complex of morphological and molecular-genetic characters. The results of phylogenetic analysis of the primary sequence of 16S rRNA gene and peculiarities of organization of secondary structures of internal transcribed spacers of ribosomal operon allowed to identify new taxa of potentially endemic cyanobacteria among the studied strains. The high level of similarity of 16S rRNA gene sequences of soil cyanobacteria with those previously detected in the water bodies of the Larsemann Hills confirms their ability to spread beyond the limits of individual ecological niches and to adapt flexibly to contrasting environmental conditions.