Acetylenotrophic and diazotrophic Bradyrhizobium sp. strain I71 from TCE-contaminated soils
Applied and Environmental Microbiology
By: Denise M. Akob, John M. Sutton, Timothy J. Bushman, Shaun Baesman, Edina Klein, Yesha Shrestha, Robert Andrews, Janna L. Fierst, Max Kolton, Sara Gushgari-Doyle, Ronald Oremland, and John Freeman
Edited by: Jeremy D. Semrau
Links
- More information: Publisher Index Page (via DOI)
- Data Release: USGS data release - Data on the Enrichment and Isolation of the Acetylenotrophic and Diazotrophic Isolate Bradyrhizobium sp. strain I71 (ver 2.0, September 2022)
- Open Access Version: External Repository
- Download citation as: RIS | Dublin Core
Abstract
Abstract
Acetylene (C2H2) is a molecule rarely found in nature, with very few known natural sources, but acetylenotrophic microorganisms can use acetylene as their primary carbon and energy source. As of 2018 there were 15 known strains of aerobic and anaerobic acetylenotrophs; however, we hypothesize there may yet be unrecognized diversity of acetylenotrophs in nature. This study expands the known diversity of acetylenotrophs by isolating the aerobic acetylenotroph, Bradyrhizobium sp. strain I71, from trichloroethylene (TCE)-contaminated soils. Strain I71 is a member of the class Alphaproteobacteria and exhibits acetylenotrophic and diazotrophic activities, the only two enzymatic reactions known to transform acetylene. This unique capability in the isolated strain may increase the genus’ economic impact beyond agriculture as acetylenotrophy is closely linked to bioremediation of chlorinated contaminants. Computational analyses indicate that the Bradyrhizobium sp. strain I71 genome contains 522 unique genes compared to close relatives. Moreover, applying a novel hidden Markov model of known acetylene hydratase (AH) enzymes identified a putative AH enzyme. Protein annotation with I-TASSER software predicted the AH from the microbe Syntrophotalea acetylenica as the closest structural and functional analog. Furthermore, the putative AH was flanked by horizontal gene transfer (HGT) elements, like that of AH in anaerobic acetylenotrophs, suggesting an unknown source of acetylene or acetylenic substrate in the environment that is selecting for the presence of AH.
Importance
The isolation of Bradyrhizobium strain I71 expands the distribution of acetylene-consuming microbes to include a group of economically important microorganisms. Members of Bradyrhizobium are well studied for their abilities to improve plant health and increase crop yields by providing bioavailable nitrogen. Additionally, acetylene-consuming microbes have been shown to work in tandem with other microbes to degrade soil contaminants. Based on genome, cultivation, and protein prediction analysis, the ability to consume acetylene is likely not widespread within the genus Bradyrhizobium. These findings suggest that the suite of phenotypic capabilities of strain I71 may be unique and make it a good candidate for further study in several research avenues.
Suggested Citation
Akob, D., Sutton, J.M., Bushman, T., Baesman, S., Klein, E., Shrestha, Y., Andrews, R., Fierst, J.L., Kolton, M., Gushgari-Doyle, S., Oremland, R., and Freeman, J., 2022, Acetylenotrophic and diazotrophic Bradyrhizobium sp. strain I71 from TCE-contaminated soils: Applied and Environmental Microbiology, v. 88, no. 22, e0129-22, 16 p., https://doi.org/10.1128/aem.01219-22.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Acetylenotrophic and diazotrophic Bradyrhizobium sp. strain I71 from TCE-contaminated soils |
| Series title | Applied and Environmental Microbiology |
| DOI | 10.1128/aem.01219-22 |
| Volume | 88 |
| Issue | 22 |
| Year Published | 2022 |
| Language | English |
| Publisher | American Society for Microbiology |
| Contributing office(s) | WMA - Laboratory & Analytical Services Division, Geology, Energy & Minerals Science Center |
| Description | e0129-22, 16 p. |
| Country | United States |
| State | California |
| City | Mountain View |
| Other Geospatial | NASA Ames Research Center |