[Activity of main enzymes of ammonium assimilation in Bradyrhizobium japonicum under the influence of plant flavonoid inductors].

The activity of key enzymes of ammonium assimilation in cell-free extracts of soybean rhizobia characterized with different effectiveness in symbiosis, has been researched. It has been found out that at highly efficient strain Bradyrhizobium japonicum UKM B-6035 the most active links in the system of ammonium assimilation reactions are glutamate synthase (glutamate-oxoglutarate-aminotransferase, GOGAT) and glutamate dehydrogenase (GDH). Whereas the most active links at the ineffective strain B. japonicum 21110 are glutamine synthetase (GS) and GDH. Under the influence of specific for soybean-rhizobia symbiosis flavonoid genistein (0.01 nm) GS-activity of the highly efficient strain has considerably increased (60.9 times), and this activity has exceeded the one of the ineffective strain more than twice. GDH has been activated in the presence of genistein in both researched strains. The nonspecific flavonoid naringenin has not stimulated GS-activity of the highly efficient rhizobia, but has stimulated the activity of GDH-way.