Nonionella stella Raw sequence reads

This project investigates the metabolic capabilities of the anaerobic foraminiferan protist Nonionella stella, which inhabits sulfur-oxidizing bacterial mats in the Santa Barbara Basin off the coast of California, USA. N. stella lives in deep-sea, aphotic environments similar to the conditions of early Earth when eukaryotes first evolved. Despite their intriguing ecological niche, the full range of their physiological functions remains poorly understood.Our study provides a detailed gene expression analysis of N. stella populations preserved in situ on the euxinic (anoxic and sulfidic) bathyal seafloor. This approach avoids environmental alterations that can occur during sample recovery, such as pressure reduction, exposure to sunlight, warming, and oxygenation.Through metatranscriptomics, metagenome-assembled genomes (MAGs), and substrate uptake measurements, we demonstrate that N. stella can generate energy in dark-euxinic conditions and perform carbon fixation via the Calvin cycle. N. stella exhibits metabolic pathways that include extended glycolysis, anaerobic fermentation, sulfide oxidation, and the presence of a membrane-bound inorganic pyrophosphatase, an enzyme hydrolyzes inorganic pyrophosphate (PPi) to actively pump protons across the mitochondrial membrane.