engleski

Resistance of indigenous Bradyrhizobium japonicum strains to moisture deficiency stress

Drought is one of the most important factors limiting nitrogen fixation, growth and yield of soybean. In this study, fifteen indigenous Bradyrhizobium japonicum strains isolated from different regions of Croatia were subjected to in vitro investigations of different drought conditions (simulated by polyethilene glycol (PEG) 6000 and increased NaCl concentrations). ERIC-PCR method was employed in order to determine genetic variability of strains. At the concentration of 15 % PEG 6000 indigenous strain B. japonicum IS1 isolated from eastern Slavonia region was most tolerant to the lack of water. At the concentraction of 30 % PEG 6000, B. japonicum IS2, was distinctively resistant to osmotic pressure, and the least tolerant was B. japonicum IS4, both isolated from eastern Slavonia. For all tested strains, good growth was observed at the concentration of 1 % NaCl and moderate growth was recorded for the strains from Koprivnica region. Indigenous strans isolated from Baranja, Istria and two from eastern Slavonia were very tolerant to high concentration of NaCl (4%). According to results of ERIC-PCR method genetic similarity was not related to location of the isolation. ERIC-PCR fingerprints revealed significant diversity between rhizobial strains regardless their sampling sites.

Glycine max (L.) Merrill, rhizobia, nitrogen fixation, in vitro drought, salt stress, ERIC-PCR

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