Algal and Fungal Diversity in Antarctic Lichens

Abstract

The composition of lichen ecosystems except mycobiont and photobiont have not been evaluated intensively. In addition, recent studies to identify algal genotypes have raised questions about the specific relationship between mycobiont and photobiont. In the current study, we analyzed algal and lichen-associated fungal community structure in lichen species from King George Island, Antarctica by pyrosequencing of eukaryotic LSU and algal ITS domains of the nuclear rRNA gene. The sequencing results of LSU and ITS regions indicated that each lichen thallus contained diverse algal species. The major algal operational taxonomic unit (OTU) defined at a 99% similarity cut-off of LSU sequences accounted for 78.7% to 100% of the total algal community in each sample. In several cases, the major OTUs defined by LSU sequences were represented by two closely related OTUs defined by 98% sequence similarity of ITS domain. The results of LSU sequences indicated that lichen-associated fungi belonged to the Arthoniomycetes, Eurotiomycetes, Lecanoromycetes, Leotiomycetes, and Sordariomycetes of the Ascomycota, and Tremellomycetes and Cystobasidiomycetes of the Basidiomycota. The composition of major photobiont species and lichen-associated fungal community were mostly related with the mycobiont species. The contribution of growth forms or substrates on composition of photobiont and lichen-associated fungi were not evident.