Genetic Diversity of Rhizobia Nodulating Phaseolus vulgaris L. from Kellem Wollega, Ethiopia

Abstract

This study was conducted to understand the genetic diversity of common bean (Phaseolus vulgaris L.) nodulating rizobia and efficacy of rhizobial isolates from the soil of various agro-ecological regions of Kellem Wollega. Soil samples were collected from six bean fields in Manjoso Jiru, Amahara Kucho, Bile, Foge, Minko, and Humbi karo using random sampling technique. The isolate were characterized using Molecular techniques through PCR-Restriction Fragment Length Polymorphism and partial sequences of 16S rDNA. From the characterization of RFLP 8IGS profiles obtained. Phylogenetic tree were created using Molecular Evolutionary Genetics Analysis version 6.0 (MEGA6), BioEdit and Multiple Sequence Comparison by Log-Expectation (MUSCLE). Then seven isolates were classified as Rhizobium leguminosarum and one isolate as Rhizobium vallis. The distributions of these strains are not the same in all study sites. For instance; R. leguminosarum is more abundant than R. vallis in all study sites. Rhizobiz vallis was only found in Humbi karo. Kellem Wollega soils harbor highly diverse rhizobial populations. The rhizobium genetic diversity is attributed to the agro-ecological region or soil characteristics of the study sites. KEY WORDS: PCR, RFLP, Phylogenetic tree, R. leguminosarum, R. vallis