Abstract EANA2026-113

Extreme environments impose multiple stressors on microbial life, including elevated temperatures, fluctuating pH, and high salinity. Microbial communities inhabiting such systems have evolved specialized biochemical and genomic adaptations. These adaptations render extremophiles particularly relevant for astrobiological research.

Saudi Arabia hosts several geothermal systems that give rise to chemically and physically diverse hot springs. Microbiological investigations of these habitats, however, have largely focused on cultivation-based studies, enzyme screening, and bioprospecting.

Here, we investigate the genomic potential of microbial communities from three Saudi Arabian hot springs, Ain al Harrah, Ain al Jumah, and Ain al Darakah, with emphasis on perchlorate reduction, a metabolism of direct relevance to Martian geochemistry.

Sediment samples were collected and subjected to short-read Illumina sequencing. Metagenome-assembled genomes (MAGs) were reconstructed, taxonomically classified, and functionally annotated using the MetaWRAP pipeline. MAGs encoding the complete perchlorate-reducing (PCR) gene cluster (pcrABCD) in consecutive order and orientation were identified. Curated Pfam profiles and manually refined PCR protein profiles were applied to reconstruct genomic islands and assess pathway completeness.

Out of 1,449 high and medium-quality MAGs, 110 encoded the full PCR operon, 43 additionally harbored the chlorite dismutase (cld) gene, and a single MAG contained the complete perchlorate reduction pathway on a single contig. This genome was affiliated with the class Binatia, lacking assignment at higher taxonomic ranks.

Ongoing experiments will evaluate the survivability and metabolic activity of fresh sediments in a Martian simulation chamber, linking genomic potential to functional performance under Mars-relevant conditions and highlighting implications for perchlorate bioremediation and astrobiology.