Diversity of Culturable Microorganisms Associated with Antarctic and Arctic Lichens

Abstract

Lichens have been regarded as symbiosis between fungi (mycobiont) and green algae or cyanobacteria (photobiont). Although the major parts of lichens are composed of mycobiont and photobiont, other microorganisms (mycobiont) also have been found to have specific relationships with lichens. Through FISH and metagenomic sequence analyses, it has been proposed that Alphaproteobacteria was the dominant bacterial taxa in the lichens. Although direct observation through in situ detection and metagenomic approaches provided lots of information on the diversity and distribution of microorganisms in the lichen tissues, studies of culturable microorganism may provide other opportunities to understand the roles of microbiont in lichen ecosystems. In the current study, we isolated 105 microbial cultures from Cetraria sp., Cladonia sp., Cladonia borealis, Flavocetraria sp., Ochrolechia sp., Psoroma sp., Rhizocarpon sp., Sterocaulon sp., Umbilicaria sp., and Usnea sp. from Arctic and Antarctic areas. Among them, fifty one bacterial isolates were included in Actinobacteria (16 isolates), Alphaproteobacteria (9 isolates), Bacteroidetes (2 isolates), Betaproteobacteria (15 isolates), Firmicutes (1 isolate), and Gammaproteobacteria (8 isolates), and fifty four fungal isolates were included in Agaricomycotina (27 isolates), Pucciniomycotina (21 isolates) and Pezizomycotina (3 isolates) . They were affiliated with Dothideomycetes, Lecanoromycetes, Cryptococcus, Mrakia, Rhodotorula, Sporobolomyces, and Tremella. Some of the species such as Burkholderia, Rhodanobacter, Sphingomonas, and Tremella were recovered from many different lichen species.