New insights into the microbial diversity of polar desert soils: A biotechnological perspective

Abstract

Microorganisms represent the most abundant cold-adapted life-forms on earth. Far from just surviving, microorganisms appear to be thriving in cold climates, with microbial richness present in polar soils often in line with temperate soils. Recent advances in molecular techniques have allowed the true extent of global microbial diversity to be revealed. Antarctica in particular, has been found to harbour diverse and unique microbial populations comprise of high proportions of Chloroflexi, Actinobacteria, and unknown, previously uncultured taxa. Microorganisms have been the targets for bioprospecting for many years but efforts have thus far largely focused on easily obtainable temperate organisms, readily cultured within the laboratory. The extreme conditions that push the limits of life within cold environments leads to the evolution of unique physiologies and functional capabilities. Actinobacteria are well known to be prolific producers of useful natural products. Their high relative abundance along with the plethora of rare and previously unknown organisms highlights the potential for new biotechnological discoveries within cold adapted microorganisms. With limited to no higher organisms, Polar soils also provide ideal model ecosystems to examine the mechanisms driving microbial patterns of distribution. Thus far microbial communities have been found to be largely endemic and exhibit spatial patterns over meter, kilometre, regional and continental scales. While the mechanisms driving the patterns are not completely understood, a number of key biotic and abiotic factors, in particular pH, C/N ratio, NH4 and N concentrations, phosphorus and plant cover, have been identified as influencing polar microbial communities and their survival in these extreme environments. Identifying and understanding key environmental drivers of microbial populations through biogeochemical analysis, structural equation models, microbial co-occurrence models, or space for time substitution studies, are providing the first step towards identifying the distribution of populations with desirable genetic or functional capacity and likewise polar regions that may contain unique communities for protection. At the same time this research is improving our capacity to predict microbial responses to disturbance due to both a changing climate and anthropogenic contamination.