A new group in the Leptospirillum clade: cultivation-independent community genomics, proteomics and transcriptomics of the new species Leptospirillum group IV UBA BS.

Journal Article · Tue Jan 01 00:00:00 EST 2013 · Applied and Environmental Microbiology

DOI:https://doi.org/10.1128/AEM.00202-13· OSTI ID:1122704

Goltsman, Daniela ^[1]; Dasari, Mauna ^[1]; Thomas, BC ^[1]; Shah, Manesh B ^[2]; Verberkmoes, Nathan C ^[2]; Banfield, Jillian F. ^[1]

---

1. University of California, Berkeley
2. ORNL

Leptospirillum spp. are widespread members of acidophilic microbial communities that catalyze ferrous iron oxidation, thereby increasing sulfide mineral dissolution rates. These bacteria play important roles in environmental acidification and are harnessed for bioleaching-based metal recovery. Known members of the Leptospirillum clade of the Nitrospira phylum are Leptospirillum ferrooxidans (group I), Leptospirillum ferriphilum and Leptospirillum rubarum (group II), and Leptospirillum ferrodiazotrophum (group III). In the Richmond Mine acid mine drainage (AMD) system, biofilm formation is initiated by L. rubarum; L. ferrodiazotrophum appears in later developmental stages. Here we used community metagenomic data from unusual, thick floating biofilms to identify distinguishing metabolic traits in a rare and uncultivated community member, the new species Leptospirillum group IV UBA BS. These biofilms typically also contain a variety of Archaea, Actinobacteria, and a few other Leptospirillum spp. The Leptospirillum group IV UBA BS species shares 98% 16S rRNA sequence identity and 70% average amino acid identity between orthologs with its closest relative, L. ferrodiazotrophum. The presence of nitrogen fixation and reverse tricarboxylic acid (TCA) cycle proteins suggest an autotrophic metabolism similar to that of L. ferrodiazotrophum, while hydrogenase proteins suggest anaerobic metabolism. Community transcriptomic and proteomic analyses demonstrate expression of a multicopper oxidase unique to this species, as well as hydrogenases and core metabolic genes. Results suggest that the Leptospirillum group IV UBA BS species might play important roles in carbon fixation, nitrogen fixation, hydrogen metabolism, and iron oxidation in some acidic environments.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1122704
• Journal Information: Applied and Environmental Microbiology, Vol. 79, Issue 17; ISSN 0099--2240
• Country of Publication: United States
• Language: English