13 To understand the mechanisms underlying the increased N2O reductase activity in the 14 Bradyrhizobium japonicum 5M09 mutant from enrichment culture under N2O respiration, we 15 analyzed the expression of genes encoding denitrification reductases and regulators. Our 16 results suggest a common regulation of nap (encoding periplasmic nitrate reductase) and nos 17 (encoding N2O reductase). 18

A novel (+)-γ-lactamase used for the resolution of racemic γ-lactam from Bradyrhizobium japonicum USDA 6 was found as a result of sequence-structure guided genome mining. It consists of 409 amino acids, only 49% of which are identical to the amino acid sequences of the known (+)-γ-lactamase from Sulfolobus solfataricus. This is only the third (+)-γ-lactamase gene to be reported.

The rhcJ and ttsI mutants of Bradyrhizobium japonicum USDA122 for the type III protein secretion system (T3SS) failed to secrete typical effector proteins and gained the ability to nodulate Rj2 soybean plants (Hardee), which are symbiotically incompatible with wild-type USDA122. This suggests that effectors secreted via the T3SS trigger incompatibility between these two partners.

Lowering oxygen tension in free-living Bradyrhizobium japonicum resulted in a dramatic switch of membrane chemistry in which phosphatidylcholine, the predominant lipid in aerated cultures, was no longer synthesized and phosphatidylethanolamine became the major lipid. Besides this change, phosphatidylinositol, a typical plant lipid rarely found in bacteria, was also synthesized.

The chemotactic response of Bradyrhizobium japonicum toward soybean seed and root exudates was examined. Assays using various isoflavones and fractionated exudate indicated that isoflavones are not the principal attractants in exudates. Likewise, induction of nod genes with isoflavones or seed exudate before assay did not enhance chemotaxis. Screening of numerous compounds revealed that only di...

Symbiotic effect of twenty one indigenous Bradyrhizobium yuanmingense strains obtained from nodules of soybean cultivated in India was comparatively evaluated with B. japonicum ASR011 on soybean cv. JS335 for improved nodulation and plant growth performance under greenhouse conditions. Significant variation in symbiotic potential among native B. yuanmingense strains was observed and few of them...

Soybean (Glycine max (L.) Merrill) is one of the most important food crops for human and animal consumption, providing oil and protein at relatively low cost. The least expensive source of nitrogen for soybean is the biological fixation of atmospheric nitrogen by the symbiotic association with soil bacteria, belonging mainly to the genus Bradyrhizobium. This study was conducted to assess the ef...

Eleven isolates of slow-growing oligotrophic bacteria from grassland soil were found to be closely related by partial 16S rRNA sequence similarity and many common taxonomic traits. Analysis of full 16S rRNA gene sequences of four representative isolates and Agromonas oligotrophica S58 indicated that they were more closely related to Bradyrhizobium japonicum, a symbiotic nitrogen-fixing bacteriu...

For Bradyrhizobium japonicum, the chemotactic and the nod gene-inducing effects of hydroxycinnamic acids and two of their derivatives were compared with those of isoflavonoids. Only the hydroxycinnamic acids were strong chemoattractants, while the other substances tested were chemotactically inactive. Besides the known nod gene induction by isoflavonoids, a weak nod gene induction by coniferyl ...

To understand the mechanisms underlying the increased N2O reductase activity in the Bradyrhizobium japonicum 5M09 mutant from enrichment culture under N2O respiration, we analyzed the expression of genes encoding denitrification reductases and regulators. Our results suggest a common regulation of nap (encoding periplasmic nitrate reductase) and nos (encoding N2O reductase).