Nodulation and delayed nodule senescence, strategies of two Bradyrhizobium japonicum isolates with high capacity to fix nitrogen

LÓPEZ, SILVINA MARIANELA YANIL; Mª DOLORES MOLINA SÁNCHEZ; GRACIELA N. PASTORINO; FRANCO, MARIO EMILIO ERNESTO; NICOLÁS TORO GARCÍA; PEDRO A. BALATTI

CURRENT MICROBIOLOGY

SPRINGER

Lugar: Berlin; Año: 2018

0343-8651

The purpose of this work was to evaluate the nodulation and nitrogen fixing capacity of two isolates, collected from fields that have been cultivated with soybean for many years, proved to be highly efficient in fixing nitrogen. We evaluated and compared the nodulation and nitrogen fixing capacity and the level of expression of regulatory as well as structural genes of nitrogen fixation and the ACC deaminase gene. We found that isolate Bradyrhizobium japonicum 163 and 366 were highly efficient to fix nitrogen. While isolate 366 develop a higher number of nitrogen fixing nodules, isolate 163 developed nodules that remained actively fixing nodules probably because the highly level of ACC deaminase reduce ethylene, retarding in this way senescence, which was confirmed by the higher levels of leghemoglobin and lower levels of ammonia found in nodules induced by isolate 163 than in nodules induced by isolate 366 and control strain E109.