Abstract Purpose In recent years, considerable research has been conducted on the use of plant growth regulators (PGRs) to improve crop yields. Large amounts PGRs are applied regulate growth. However, few studies have assessed impact PGRs, which leave soil residues, microorganisms, especially rhizobia. Methods this study, influence inoculation soybean roots with Sinorhizobium fredii and Bradyrh...

Two Sinorhizobium meliloti strains (1021 and NitR) were used for inoculation of alfalfa plants to study nitrogen assimilation under nutrient deficiency conditions in hydroponics experiments. The wild type Sinorhizobium meliloti 1021 was compared with a mutant strain – S. meliloti NitR. NitR protein was found to be a regulator of S. meliloti hmgA expression under nitrogen deprivation conditions,...

Suppression of host innate immunity appears to be required for the establishment of symbiosis between rhizobia and host plants. In this study, we established a system that included a host plant, a bacterial pathogen and a symbiotic rhizobium to study the role of innate immunity during symbiotic interactions. A pathogenic bacterium, Pseudomonas syringae pv. tomato strain DC3000 (Pst DC3000), was...

Nodulation of soybean (Glycine max) root hairs by the nitrogen-fixing symbiotic bacterium Bradyrhizobium japonicum is a complex process coordinated by the mutual exchange of diffusible signal molecules. A metabolomic study was performed to identify small molecules produced in roots and root hairs during the rhizobial infection process. Metabolites extracted from roots and root hairs mock inocul...

Infection of soybean root hairs by Bradyrhizobium japonicum is the first of several complex events leading to nodulation. In the current proteomic study, soybean root hairs after inoculation with B. japonicum were separated from roots. Total proteins were analyzed by two-dimensional (2-D) polyacrylamide gel electrophoresis. In one experiment, 96 protein spots were analyzed by matrix-assisted la...

Seed treatments with Bacillus cereus UW85 increased nodulation of soybeans in three field seasons and in three different sterilized soils in the growth chamber. In the field, 28 and 35 days after planting, UW85-treated plants had 31 to 133% more nodules than untreated plants. From 49 days after planting until seed harvest, there were no significant differences between nodulation of UW85-treated...