Bradyrhizobium ottawaense sp. nov., a symbiotic nitrogen fixing bacterium from root nodules of soybeans in Canada

Abstract

Sixteen strains of symbiotic bacteria from root nodules of Glycine max grown in Ottawa, Canada, were previously characterized and placed in a novel group within the genus Bradyrhizobium. To verify their taxonomic status, these strains were further characterized using a polyphasic approach. All strains possessed identical 16S rRNA gene sequences that were 99.79 % similar to the closest relative, Bradyrhizobium liaoningense LMG 18230T. Phylogenetic analysis of concatenated atpD, glnII, recA, gyrB, rpoB and dnaK genes divided the 16 strains into three multilocus sequence types that were placed in a highly supported lineage distinct from named species of the genus Bradyrhizobium consistent with results of DNA–DNA hybridization. Based on analysis of symbiosis gene sequences (nodC and nifH), all novel strains were placed in a phylogenetic group with five species of the genus Bradyrhizobium that nodulate soybeans. The combination of phenotypic characteristics from several tests including carbon and nitrogen source utilization and antibiotic resistance could be used to differentiate representative strains from recognized species of the genus Bradyrhizobium. Novel strain OO99T elicits effective nodules on Glycine max, Glycine soja and Macroptilium atropurpureum, partially effective nodules on Desmodium canadense and Vigna unguiculata, and ineffective nodules on Amphicarpaea bracteata and Phaseolus vulgaris. Based on the data presented, we conclude that our strains represent a novel species for which the name Bradyrhizobium ottawaense sp. nov. is proposed, with OO99T ( = LMG 26739T = HAMBI 3284T) as the type strain. The DNA G+C content is 62.6 mol%.

Cicer canariense, an endemic legume to the Canary Islands, is nodulated in mainland Spain by fast-growing strains from symbiovar trifolii phylogenetically related to Rhizobium leguminosarum

“…S1A and S1B) from which ten fast-growing rhizobial strains isolated on YMA medium were shown to be genetically diverse after RAPD pattern analysis, which is a technique allowing differentiation between rhizobial strains from different genera [8,28,41]. The results of this analysis revealed that the strains isolated from C. canariense nodules displayed six different RAPD patterns (Fig.…”

“…The analysis of the recA and atpD housekeeping genes allows the differentiation of rhizobia at the species level and they are available for most described species able to nodulate legumes to date [14,40,41]. The similarity values for the recA and atpD genes among the isolated strains ranged from 98.7% to 97.1% and 98.8% to 90.1%, respectively.…”

Invasive Galega officinalis (Goat's rue) plants in Canada form a symbiotic association with strains of Neorhizobium galegae sv. officinalis originating from the Old World

“…Bayesian phylogenetic trees were inferred using MrBayes version 3.2.1 (Altekar, Dwarkadas, Huelsenbeck, & Ronquist, 2004) with default priors as previously described (Yu, Cloutier, Tambong, & Bromfield, 2014); Maximum Likelihood (ML) trees (Guindon et al, 2010) were inferred as detailed by Tang et al (2012) Ontario, were surface sterilized, grown in axenic Leonard jar assemblies supplied with nitrogen-free nutrient solution (Tang et al, 2012) and inoculated with soil suspensions (1:1, soil:water). Plants were maintained in a temperature-controlled growth chamber for 35 days using conditions described by Bromfield et al (2010).…”

Symbiotic efficiency and genetic diversity of soybean bradyrhizobia in Brazilian soils

“…icense (Durán et al, 2014a,b), B. manausense (Silva et al, 2014a), B. ingae (Silva et al, 2014b), B. valentinum (Durán et al, 2014a,b), B. neotropicale (Zilli et al, 2014), B. ottawaense (Yu et al, 2014), B. erythrophlei and B. ferriligni (Yao et al, 2015). The number of described novel species has increased in the past two years along with the use of appropriate molecular techniques, such as housekeeping gene analysis (Willems et al, 2001;Martens et al, 2008;Rivas et al, 2009), as well as the study of new host plants and unexplored geographic regions.…”