Connectivity of edaphic and endolithic microbial niches in cold mountain desert of eastern pamir (Tajikistan)

Microbial communities found in arid environments are commonly represented by biologicalsoil crusts (BSCs) and endolithic assemblages. There is still limited knowledge concerning endolithsand BSCs occurring in the cold mountain desert of Pamir. The aim of the study was to investigate thecomposition and structure of endolithic bacterial communities in comparison to surrounding BSCs inthree subregions of the Eastern Pamir (Tajikistan). The endolithic and BSC communities were studiedusing culture-independent and culture dependent techniques. The structure of the endolithic bacte-rial communities can be characterized as Actinobacteria–Proteobacteria–Bacteroidetes–Chloroflexi–Cyanobacteria, while the BSCs’ can be described as Proteobacteria–Actinobacteria–Bacteroidetes–Cyanobacteria assemblages with low representation of other bacteria. The endolithic cyanobacterialcommunities were characterized by the high percentage of Chroococcidiopsaceae, Nodosilineaceae,Nostocaceae and Thermosynechococcaceae, while in the BSCs were dominated by Nodosilineaceae,Phormidiaceae and Nostocaceae. The analysis of 16S rRNA genes of the cyanobacterial culturesrevealed the presence of possibly novel species of Chroococcidiopsis,Gloeocapsopsis and Wilmottia.Despite the niches’ specificity, which is related to the influence of microenvironment factors onthe composition and structure of endolithic communities, our results illustrate the interrelationbetween the endoliths and the surrounding BSCs in some regions. The structure of cyanobacterialcommunities from BSC was the only one to demonstrate some subregional differences.This research was funded by the National Science Centre, grant number 2015/19/B/NZ9/00473 (I.J.), the Ministry of Science and Higher Education through the Faculty of Biology, University of Warsaw intramural grant number DSM501-D114-86-0117600-16 (N.K.), by the grant PID2019-105469RB-C22, AEI, MICINN (A.d.l.R.), and Integrated Development Programme (ZIP) of the University of Warsaw (N.K.).Peer reviewe