Two methods of soybean seeds inoculation by Rhizobium japonicum have been compared in a field experiment : i) traditional use of inoculated turf embedding the seeds; ii) use of Cephalobus parvus as bacterial carrier (3 O00 and 300 O00 nematodes per linear meter). There is no difference in yield between the inoculation methods in spite of a greater number of bacterial germs provided by nematode ...

Previous research has shown that a significant limitation to the agricultural use of improved rhizobial inoculant strains is competition from the indigenous soil population. In this work, we sought to test whether chemical inhibitors of flavonoid-induced nod gene expression in Bradyrhizobium japonicum could be identified and utilized to affect interstrain competition for nodulation of soybeans....

In this study the symbiotic interactive effect of different Bradyrhizobium japonicum strains with six soybean cultivars were evaluated under fi eld conditions. The rhizobial strains ASR011, USDA123 and CB1809 respectively showed hostcultivar specifi city with JS335, Lee and Bragg. B. japonicum ASR011 recorded the highest nodulation and nitrogenase activity with all the studied cultivars. Genera...

Several isolates of Rhizobium fredii were examined for their serological relatedness to each other, to Bradyrhizobium japonicum, and to other fast- and slow-growing rhizobia. Immunofluorescence, agglutination, and immunodiffusion analyses indicated that R. fredii contains at least three separate somatic serogroups, USDA 192, USDA 194, and USDA 205. There was no cross-reaction between any of the...

We investigated the relationship between the genetic diversity of indigenous soybean-nodulating bradyrhizobia and their geographical distribution in the United States using nine soil isolates from eight states. The bradyrhizobia were inoculated on three soybean Rj genotypes (non-Rj, Rj(2)Rj(3), and Rj(4)). We analyzed their genetic diversity and community structure by means of restriction fragm...

A novel extracellular low-molecular-weight polysaccharide was detected as a contaminant within extracellular cyclic beta-1,6-beta-1,3-glucan preparations from Bradyrhizobium japonicum USDA 110 cultures. Compositional analysis, methylation analysis, and nuclear magnetic resonance analysis revealed that this low-molecular-weight polysaccharide was composed of the same pentasaccharide repeating un...

To elucidate how temperature affects bradyrhizobial ecology, long-term incubations of Bradyrhizobium japonicum USDA 6(T), 38, and 123 and of Bradyrhizobium elkanii USDA 76(T) were conducted under various temperature conditions. Proliferative traits in liquid culture and population occupancies in soil microcosms were compared. The occupancies of USDA 76(T) and USDA 123 in soil microcosms during ...

Bradyrhizobium embrapense CNPSo 2833T is a nitrogen-fixing symbiont of the legume pasture Desmodium. Its draft genome contains 8,267,832bp and 7876 CDSs. The symbiotic island includes nodulation and nitrogen fixation genes resembling the operon organization of B. japonicum. Several CDSs related to secretion proteins and stress tolerance were also identified.

Soybean bradyrhizobia form root nodules on soybean plants and symbiotically fix N2 Strain J5 is phylogenetically far from well-known representatives within the Bradyrhizobium japonicum linage. The complete genome showed the largest single chromosomal (10.1 Mb) and symbiosis island (998 kb) among complete genomes of soybean bradyrhizobia.

We present here the complete genome sequence of Bradyrhizobium japonicum strain E109, one of the most used rhizobacteria for soybean inoculation in Argentina since the 1970s. The genome consists of a 9.22-Mbp single chromosome and contains several genes related to nitrogen fixation, phytohormone biosynthesis, and a rhizospheric lifestyle.