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Desulfovibrio diazotrophicus sp. nov., a sulfate‐reducing bacterium from the human gut capable of nitrogen fixation
Author(s) -
Sayavedra Lizbeth,
Li Tianqi,
Bueno Batista Marcelo,
Seah Brandon K. B.,
Booth Catherine,
Zhai Qixiao,
Chen Wei,
Narbad Arjan
Publication year - 2021
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.15538
Subject(s) - biology , nitrogen fixation , nitrogenase , bacteria , desulfovibrio , microbiology and biotechnology , metagenomics , gene , biochemistry , genetics
Summary Sulfate‐reducing bacteria (SRB) are widespread in human guts, yet their expansion has been linked to colonic diseases. We report the isolation, sequencing and physiological characterization of strain QI0027 T , a novel SRB species belonging to the class Desulfovibrionia . Metagenomic sequencing of stool samples from 45 Chinese individuals, and comparison with 1690 Desulfovibrionaceae metagenome‐assembled genomes recovered from humans of diverse geographic locations, revealed the presence of QI0027 T in 22 further individuals. QI0027 T encoded nitrogen fixation genes and based on the acetylene reduction assay, actively fixed nitrogen. Transcriptomics revealed that QI0027 T overexpressed 42 genes in nitrogen‐limiting conditions compared to cultures supplemented with ammonia, including genes encoding nitrogenases, a urea uptake system and the urease complex. Reanalyses of 835 public stool metatranscriptomes showed that nitrogenase genes from Desulfovibrio bacteria were expressed in six samples suggesting that nitrogen fixation might be active in the gut environment. Although frequently thought of as a nutrient‐rich environment, nitrogen fixation can occur in the human gut. Animals are often nitrogen limited and have evolved diverse strategies to capture biologically active nitrogen, ranging from amino acid transporters to stable associations with beneficial microbes that provide fixed nitrogen. QI0027 T is the first Desulfovibrio human isolate for which nitrogen fixation has been demonstrated, suggesting that some sulfate‐reducing bacteria could also play a role in the availability of nitrogen in the gut.