Microbial response to seasonal variation in arctic biocrusts with a focus on fungi and cyanobacteria
Ekaterina Pushkareva, Eva Hejduková, Josef Elster, Burkhard Becker
Abstract
Biocrusts are crucial components of Arctic ecosystems, playing significant roles in carbon and nitrogen cycling, especially in regions where plant growth is limited. However, the microbial communities within Arctic biocrusts and their strategies for surviving the harsh conditions remain poorly understood. In this study, the microbial profiles of Arctic biocrusts across different seasons (summer, autumn, and winter) were investigated in order to elucidate their survival strategies in extreme conditions. Metagenomic and metatranscriptomic analyses revealed significant differences in microbial community composition among the sites located in different elevations. The bacterial communities were dominated by Actinobacteria and Proteobacteria, while the fungal communities were mainly represented by Ascomycota and Basidiomycota, with lichenized and saprotrophic traits prevailing. Cyanobacteria were primarily composed of heterocystous cyanobacteria. Furthermore, the study identified molecular mechanisms underlying cold adaptation, including the expression of heat shock proteins and cold-inducible RNA helicases in cyanobacteria and fungi. Overall, the microbial communities appear to be permanently well adapted to the extreme environment. • The microbial communities of biocrusts appear to be permanently well adapted to the extreme environment in the Arctic. • RNA helicases and heat shock proteins play an important role in the cold acclimation of cyanobacteria and fungi in Arctic biocrusts. • Nostoc is a key genus of cyanobacteria in Arctic biocrusts. • Lichenized and saprotrophic traits dominate the fungal community in the Arctic biocrusts.