Bacterial communities in Antarctic lichens

Abstract

So far, many studies to survey the bacterial communities in lichen thalli from diverse geographical areas have shown that Alphaproteobacteria is a predominating bacterial class in most lichens. In this study, we analyzed bacterial communities in several Antarctic lichens with different growth form and substrates. Bacterial community composition in fruticose and foliose lichens, Cladonia, Umbilicaria, Usnea, and crustose lichens, Buelia granulosa, Amandinea coniops, and Ochrolechia parella from King George Island, Antarctica was analyzed by pyrosequencing of bacterial 16S rRNA gene. Results showed that Proteobacteria, Acidobacteria, Actinobacteria, and Bacteroidetes were predominant phyla. The predominant bacterial class in most of the samples was Alphaproteobacteria, which have also been found previously in other lichen species. Acetobacteriaceae of the order Rhodospiralles in Alphaproteobacteria was the most abundant bacterial family in Antarctic lichens. The LAR1 lineage of the order Rhizobiales, a putative N-fixer which has been frequently observed in lichens from temperate area, was detected only from few samples at low frequency. It is expected that other bacterial taxa are working as N-fixer in Antacrtic lichens. From the PcoA analysis of fastUniFrac distance matrix, it was proposed that microbial community structures in Antarctic lichens were affected by host species, growth form, and substrates.