Bezuidt, Keoagile Ignatius OliverLebre, Pedro HumbertoPierneef, Rian EwaldLeon-Sobrino, CarlosAdriaenssens, Evelien M.Cowan, Don A.Van de Peer, YvesMakhalanyane, Thulani Peter2021-05-212021-05-212020-05-05Bezuidt OKI, Lebre PH, Pierneef R, León-Sobrino C, Adriaenssens EM, Cowan DA, Van de Peer Y, Makhalanyane TP. 2020. Phages actively challenge niche communities in Antarctic soils. mSystems 5:e00234-20. https://DOI.org/ 10.1128/mSystems.00234-20.2379-5077 (online)10.1128/mSystems.00234-20http://hdl.handle.net/2263/79991By modulating the structure, diversity, and trophic outputs of microbial communities, phages play crucial roles in many biomes. In oligotrophic polar deserts, the effects of katabatic winds, constrained nutrients, and low water availability are known to limit microbial activity. Although phages may substantially govern trophic interactions in cold deserts, relatively little is known regarding the precise ecological mechanisms. Here, we provide the first evidence of widespread antiphage innate immunity in Antarctic environments using metagenomic sequence data from hypolith communities as model systems. In particular, immunity systems such as DISARM and BREX are shown to be dominant systems in these communities. Additionally, we show a direct correlation between the CRISPR-Cas adaptive immunity and the metavirome of hypolith communities, suggesting the existence of dynamic host-phage interactions. In addition to providing the first exploration of immune systems in cold deserts, our results suggest that phages actively challenge niche communities in Antarctic polar deserts. We provide evidence suggesting that the regulatory role played by phages in this system is an important determinant of bacterial host interactions in this environment.en© 2020 Bezuidt et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.Antarctic soilsArchaeaBacteriaHypolithsPhagesViromicsArticle