Diversity among Field Populations of Bradyrhizobium japonicum in Poland

Abstract

Genetic structure in field populations of Bradyrhizobium japonicum isolated in Poland was determined by using several complementary techniques. Of the 10 field sites examined, only 4 contained populations of indigenous B. japonicum strains. The Polish bradyrhizobia were divided into at least two major groups on the basis of protein profiles on polyacrylamide gels, serological reaction with polyclonal antisera, repetitive extragenic palindromic PCR fingerprints of genomic DNA, and Southern hybridization analyses with nif and nod gene probes. Serological analyses indicated that 87.5% of the Polish B. japonicum isolates tested were in serogroups 123 and 129, while seven (12.5%) of the isolates tested belonged to their own unique serogroup. These seven strains also could be grouped together on the basis of repetitive extragenic palindromic PCR fingerprints, protein profiles, and Southern hybridization analyses. Cluster analyses indicated that the seven serologically undefined isolates were genetically dissimilar from the majority of the Polish B. japonicum strains. Moreover, immuno-cross-adsorption studies indicated that although the Polish B. japonicum strains reacted with polyclonal antisera prepared against strain USDA123, the majority failed to react with serogroup 123-and 129-specific antisera, suggesting that Polish bradyrhizobia comprise a unique group of root nodule bacteria which have only a few antigens in common with strains USDA123 and USDA129. Nodulation studies indicated that members of the serologically distinct group were very competitive for nodulation of Glycine max cv. Nawiko. None of the Polish serogroup 123 or 129 isolates were restricted for nodulation by USDA123-and USDA129-restricting soybean plant introduction genotypes. Taken together, our results indicate that while genetically diverse B. japonicum strains were isolated from some Polish soils, the majority of field sites contained no soybean-nodulating bacteria. In addition, despite the lack of long-term soybean production in Poland, field populations of unique B. japonicum strains are present in some Polish soils and these strains are very competitive for nodulation of currently used Polish soybean varieties.

Characterization of Rhizobia for the Improvement of Soybean Cultivation at Cold Conditions in Central Europe

“…Furthermore, these German indigenous rhizobia are distributed in fields with soybean cultivation histories, which indicates that the natural population of rhizobia have been affected by both the cultivation of different legume crops and the application of inoculants. These results are supported by other investigations in Europe, such as Poland and Spain, and also in Africa (Madrzak et al, 1995;Bourebaba et al, 2016;Chibeba et al, 2017).…”

Phenotypic and molecular characterization of chickpea rhizobia isolated from different areas of Morocco

“…Indeed, all isolates of cluster III and most of those of cluster I which tolerate 1AE5% NaCl and higher concentrations were isolated from saline soils. Regarding the intrinsic resistance to antibiotics, it has been reported that fast-growing strains are more sensitive to antibiotics (Jordan 1984) than slow-growing rhizobia (Madrzak et al 1995). Conversely, in our study, chickpea rhizobial strains which are a mixture of fast, slow and extra-slow growers, showed a wide range of behaviour with regard to antibiotics and heavy metals.…”

Lipopolysaccharide Profiles from Nodules as Markers of Bradyrhizobium Strains Nodulating Wild Legumes

“…Our data did not support either of these alternatives. The diversity that we have found in the population studied was higher than the diversity found in other studies (3,4,6,12,14,15,20). As any individual method detects only a fraction of the total strains in a population (24) and the strains recovered from nodules may be only a fraction of soil population (5), the number of different Adenocarpus-nodulating strains in the Tenerife forest could be enormous.…”