Genetic diversity of rhizobia associated with Pisum sativum L. in the Northern part of Turkey

In this study, the diversity of root-nodulating bacteria associated with Pisum sativum L. cultivated in the Eastern and Western Black Sea regions (11 provinces) and three provinces in the Marmara region were investigated. rDNA-ITS RFLP analysis revealed nine groups within the 40 isolates collected in the study. Based on the phylogenetic analysis of the recA, atpD and glnII genes, isolates within the RFLP groups were assigned to the following Rhizobium species; Group-I: R. laguerreae; Groups -II and -IV: R. ruizarguesonis; Groups -III, -V, -VII, -VIII: genospecies-B (gsB) of the R. leguminosarum complex (Rlc); Group-VI: Rlc gsE; and Group-IX: Rlc gsA. From the nodC-RFLP analysis and phylogenetic analysis of the nodC gene, all rhizobial isolates obtained in this study were assigned to the symbiovar. viciae variety of the related Rhizobium species. In this study, Rlc gsB (n: 19) was the species that most commonly caused the nodulation of P. sativum in the northern Anatolia, followed by R. ruizarguesonis (n: 8). Rhizobium laguerreae (n: 5) was a widespread but not common species, and Rlc gsA (n: 3) and Rlc gsE (n: 5) had a distribution limited to the Eastern and Western Black Sea regions, respectively. Overall, results obtained from species diversity analysis, nodC phylogenetic analysis and nodX analysis suggest a common phylogeographic history for pea-nodulating rhizobia in northern Anatolia and western Europe. Separately, this study presents the first reports of R. laguerreae and R. ruizarguesonis from P. sativum root nodules in Turkey and the first report of R. ruizarguesonis outside of Europe.