Biological nitrogen fixation is a key process for agricultural production and environmental sustainability, but there are comparatively few studies of symbionts of tropical pasture legumes, as well as few described species of the genus Bradyrhizobium, although it is the predominant rhizobial genus in the tropics. A detailed polyphasic study was conducted with two strains of the genus Bradyrhizobium used in commercial inoculants for tropical pastures in Brazil, CNPSo 1112T, isolated from perennial soybean (Neonotonia wightii), and CNPSo 2833T, from desmodium (Desmodium heterocarpon). Based on 16S-rRNA gene phylogeny, both strains were grouped in the Bradyrhizobium elkanii superclade, but were not clearly clustered with any known species. Multilocus sequence analysis of three (glnII, gyrB and recA) and five (plus atpD and dnaK) housekeeping genes confirmed that the strains are positioned in two distinct clades. Comparison with intergenic transcribed spacer sequences of type strains of described species of the genus Bradyrhizobium showed similarity lower than 93.1 %, and differences were confirmed by BOX-PCR analysis. Nucleotide identity of three housekeeping genes with type strains of described species ranged from 88.1 to 96.2 %. Average nucleotide identity of genome sequences showed values below the threshold for distinct species of the genus Bradyrhizobium ( < 90.6 %), and the value between the two strains was also below this threshold (91.2 %). Analysis of nifH and nodC gene sequences positioned the two strains in a clade distinct from other species of the genus Bradyrhizobium. Morphophysiological, genotypic and genomic data supported the description of two novel species in the genus Bradyrhizobium, Bradyrhizobium tropiciagri sp. nov. (type strain CNPSo 1112T = SMS 303T = BR 1009T = SEMIA 6148T = LMG 28867T) and Bradyrhizobium embrapense sp. nov. (type strain CNPSo 2833T = CIAT 2372T = BR 2212T = SEMIA 6208T = U674T = LMG 2987).
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1099/ijsem.0.000592 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Closed genomes of commercial inoculant rhizobia provide a blueprint for management of legume inoculation.
Appl Environ Microbiol
January 2025
Legume Rhizobium Sciences, Food Futures Institute, Murdoch University, Murdoch, Western Australia, Australia.
Unlabelled: Rhizobia are soil bacteria capable of establishing symbiosis within legume root nodules, where they reduce atmospheric N into ammonia and supply it to the plant for growth. Australian soils often lack rhizobia compatible with introduced agricultural legumes, so inoculation with exotic strains has become a common practice for over 50 years. While extensive research has assessed the N-fixing capabilities of these inoculants, their genomics, taxonomy, and core and accessory gene phylogeny are poorly characterized.
View Article and Find Full Text PDFRevitalizing Soybean Plants in Saline, Cd-Polluted Soil Using Si-NPs, Biochar, and PGPR.
Plants (Basel)
December 2024
Department of Agricultural Microbiology, Agriculture and Biology Research Institute, National Research Centre, 33 EI Buhouth St., Dokki, Cairo 12622, Egypt.
Excessive irrigation of saline-alkaline soils with Cd-contaminated wastewater has resulted in deterioration of both soil and plant quality. To an investigate this, a study was conducted to explore the effects of biochar (applied at 10 t ha), PGPRs ( (USDA 110) + at 1:1 ratio), and Si-NPs (25 mg L) on soybean plants grown in saline-alkali soil irrigated with wastewater. The results showed that the trio-combination of biochar with PGPRs, (as soil amendments) and Si-NPs (as foliar spraying), was more effective than individual or coupled applications in reducing Cd bioavailability in the soil, minimizing its absorption, translocation and bioconcentration in soybean tissues.
View Article and Find Full Text PDFDual Screen for Metal-Tolerant Metallophore Producers Evaluated with Soil from the Carpenter Snow Creek Site, a Heavy-Metal-Toxified Site in Montana.
ACS Omega
December 2024
Boudreau Lab, Department of Biomolecular Science, School of Pharmacy, University of Mississippi, Faser Hall University, University, Mississippi 38677-1848, United States.
Bacteria have evolved numerous mechanisms to resist metal toxicity, including small-molecule metal chelators (metallophores). This study presents a dual screening methodology to isolate metallophore-producing bacteria from the Carpenter Snow Creek Mining District for potential use in heavy-metal bioremediation. Soil samples were screened on metal-supplemented plates from which colonies were picked onto chrome azurol S (CAS)-dyed plates.
View Article and Find Full Text PDFDifferential insights into the distribution characteristics of bacterial communities and their response to typical pollutants in the sediment and soil of large drinking water reservoir.
J Environ Manage
January 2025
School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China. Electronic address:
In this study, a large drinking water reservoir (Fengshuba Reservoir) was chosen as a representative case, and the bacterial communities in the sediments and soils of Water-level fluctuating zone (WLFZ) as well as their responses to heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) were systematically investigated. The results indicated that the abundance and diversity of the bacterial community obviously changed with seasonal hydrological variations in sediments, and the absolute abundance and composition of bacteria community differed significantly between the sediment phase and soil phase. Bacteria with the ability to degrade pollutants rapidly proliferate and gain ascendancy in the soil phase, with Burkholderia-Caballeronia-Paraburkholderia (B-C-P) and Bradyrhizobium forming the core of the largest community.
View Article and Find Full Text PDFPhosphate addition intensifies the increase in NO emission under nitrogen deposition in wet meadows of the Qinghai-Tibet Plateau.
Front Microbiol
December 2024
College of Forestry, Gansu Agricultural University, Lanzhou, China.
Alpine wet meadows are known as NO sinks due to nitrogen (N) limitation. However, phosphate addition and N deposition can modulate this limitation, and little is known about their combinative effects on NO emission from the Qinghai-Tibet Plateau in wet meadows. This study used natural wet meadow as the control treatment (CK) and conducted experiments with N (CONH addition, N15), P (NaHPO addition, P15), and their combinations (CONH and NaHPO addition, N15P15) to investigate how N and P supplementation affected soil NO emissions in wet meadow of QTP.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!