Diversity of protists in dryland habitats of Qatar revealed by environmental metabarcoding

We investigated soil protist communities across five sites representing two characteristic dryland habitats in Qatar: rawdha and sabkha. Altogether, 100 samples were collected during a single field campaign; DNA was subsequently extracted, and the V4 region of the 18S rRNA gene was amplified. We obtained 112,529 high-quality sequences, taxonomically representing 1,524 TSAR (Telonemia, Stramenopila, Alveolata, Rhizaria) amplicon sequence variants. This approach enabled detection of diverse eukaryotic lineages and facilitated assessment of their diversity and relative abundance. Protist diversity differed significantly between habitats and among samples, while richness varied significantly between habitats. Across all samples, 170 genera were identified, of which 52 were shared across all sites. Sabkha exhibited the highest number of exclusive genera (22), nearly three times the number found in any individual rawdha site. The clade Alveolata accounted for 50 % or more of overall genus richness in most samples. Among ciliates, the classes Spirotrichea and Colpodea were the most abundant at the time of sampling. Functional analysis revealed consumers as the dominant trophic group. This study advances our understanding of microbial life in extremely hot environments by uniquely comparing two proximate terrestrial habitats that, despite similar climatic conditions, exhibit distinct edaphic and physicochemical characteristics.