Shewanella sp. FeAMO (=MCCC M27737) and Shewanella sp. JL219SE-S6 (=MCCC M29292) were isolated from hydrothermal sediments from Wocan-1 hydrothermal field (6°22'N, 60°32'E, at a depth of 2995 m) and Tianxiu hydrothermal field (3°41'N, 63°50'E, at a depth of 3642 m), respectively, on the Carlsberg Ridge in the Northwest Indian Ocean. They are Gram-negative, rod-shaped, facultatively anaerobic iron-reducing bacteria, with optimal growth and iron reduction at approximately 28 °C, utilizing lactate, formate, peptone, and H₂ as electron donors and FeOOH, Fe₂O₃, or Fe₃O₄-containing minerals as electron acceptors. The complete genomes were sequenced using a hybrid approach with both Illumina HiSeq and PacBio Sequel IIe platforms (assembled with Unicycler v0.4.8). Shewanella sp. FeAMO has one circular chromosome (4,982,876 bp, 52.92% GC content) and one circular plasmid (7048 bp, 46.06% GC content), totaling 4369 coding DNA sequences (CDSs), 106 tRNA genes, and 25 rRNA genes; Shewanella sp. JL219SE-S6 has a single circular chromosome (4,996,394 bp, 53.09% GC content) with 5344 CDSs, 107 tRNA genes, and 25 rRNA genes. Genomic analysis revealed key functional modules, including the complete Mtr pathway and Feo system for iron reduction/transport, heavy metal (copper, cobalt‑zinc‑cadmium) efflux systems (copAR/cusABRS, czcABCD), a TMAO reductase system (torACRST), and numerous flagellar and fimbrial-related proteins for motility/adhesion. These findings provide insights into the mechanisms of environmental adaptation of Shewanella in deep-sea hydrothermal sediments.
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