The symbiosis between oriental goat’s rue and the root nodule bacteria Rhizobium galegae: Specificity and competitiveness

Competitiveness and genetic variation of the Rhizobium galegae strains from the collection of the All-Russia Institute of Agricultural Microbiology, Russian Academy of Agricultural Sciences, causing nodulation of oriental goat’s rue under conditions of Bashkortostan soils (lacking this rhizobial species) were studied. It was demonstrated that of all the tested strains, the strains CIAM 0702 and CIAM 0704, each carrying two megaplasmids of 1500 and 2000 MDa, were the most competitive. RAPD (random amplified polymorphic DNA) analysis showed that R. galegae strains were able to intensively exchange the genetic material in the host plant rhizosphere. We did not succeed in detecting the local root nodule bacteria that were either initially able to infect oriental goat’s rue or had adapted to infecting this species due to various genetic rearrangements.