Different species and symbiotic genotypes of field rhizobia can nodulate Phaseolus vulgaris in Tunisian soils

摘要: A collection of 160 isolates rhizobia nodulating Phaseolus vulgaris in three geographical regions Tunisia was characterized by restriction fragment length polymorphism analysis polymerase chain reaction (PCR)-amplified 16S rDNA, nifH and nodC genes. Nine groups were delineated: Rhizobium gallicum biovar (bv.) gallicum, leguminosarum bv. phaseoli viciae, etli phaseoli, giardinii giardinii, four related to species the genus Sinorhizobium, Sinorhizobium meliloti, medicae fredii. The most abundant rhizobial R. etli, encompassing 29–20% each. Among assigned leguminosarum, two-thirds ineffective nitrogen fixation with P. harbored a symbiotic gene typical viciae. S. fredii-like did not nodulate soybean plants but formed numerous effective nodules on vulgaris. Comparison sequences showed that their genotype fredii, reference strain GR-06, which isolated from bean plant grown Spanish soil. An additional including 16% found be closely Agrobacterium. However, when re-examined, these original host.