Original scientific paper
https://doi.org/10.5513/JCEA01/20.4.2436
Phenotypic and genotypic diversity of Sinorhizobium meliloti strains isolated from soils in Zadar County
Sanja Kajić
orcid.org/0000-0001-8869-5131
; University of Zagreb, Faculty of Agriculture, Department of Microbiology, Svetošimunska cesta 25, 10000 Zagreb, Croatia
Mihaela Blažinkov
; College of Slavonski Brod, Dr. Mile Budaka 1, 35000 Slavonski Brod, Croatia
Ivana Rajnović
; University of Zagreb, Faculty of Agriculture, Department of Microbiology, Svetošimunska cesta 25, 10000 Zagreb, Croatia
Nikolina Burek Svetec
; University of Zagreb, Faculty of Agriculture, Department of Microbiology, Svetošimunska cesta 25, 10000 Zagreb, Croatia
Melita Lekčević
; University of Zagreb, Faculty of Agriculture, Department of Microbiology, Svetošimunska cesta 25, 10000 Zagreb, Croatia
Sanja Sikora
; University of Zagreb, Faculty of Agriculture, Department of Microbiology, Svetošimunska cesta 25, 10000 Zagreb, Croatia
Abstract
Soil bacteria, Sinorhizobium melilo i is of great agricultural importance because of its ability to fix atmospheric nitrogen in symbiosis with alfalfa, a very valuable forage crop. The main aim of this study was to evaluate tolerance of indigenous S. melilo i strains to stress environmental conditions. Twenty rhizobial strains, isolated from different regions in Croatia, were genotipically characterized to assess diversity amongst natural population. Stress tolerance assays were performed in order to select indigenous rhizobia with tolerance to unfavorable soil conditions. The growth of the strains was studied at different pH values, temperatures, NaCl and heavy metals concentrations. The results of 16S rDNA genotyping using PCR/RFLP analysis showed that 17 isolates could be assigned to S. melilo i while RAPD and ERIC-PCR fingerprints revealed significant genetic diversity among indigenous rhizobial strains. In comparison to the reference strain, higher resistance to adverse growth conditions of indigenous S. melilo i strains was determined. Most of the strains grew at temperatures higher than optimal and tolerated both acidic and alkaline environment. It was found that indigenous strains tolerate extremely high NaCl concentrations. Better understanding of rhizobial response to adverse environmental conditions is of potential value for improving rhizobial inoculants and efficiency of symbiotic nitrogen fixation
Keywords
nitrogen fixation; indigenous strains; Sinorhizobium meliloti; genetic diversity; phenotypic characterization
Hrčak ID:
230872
URI
Publication date:
19.12.2019.
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