Isolation and purification of Rhizobium from French bean (Phaseolus vulgaris L.) root nodules

"Six rhizobial isolates were collected from root nodules of Phaseolus vulgaris plants and isolates were designated as Rb1. the majority of the isolates were rapid growers within the medium and growth obtained on 3- 5 days of the incubation whereas a few of the isolates were slow growers and growth obtained on 3-4 days. Rhizobial colonies in Yeast Extract Mannitol Agar (YEMA) medium were round mucoid and white. Under microscopic examination, bacteria appeared as nonmotile, gram negative rod shaped. The Rhizobial isolates was characterized based on the growth behavior in the medium of Congo red, Hofer’s alkaline broth and polyhydroxy butyrate staining. All of these tests confirmed that findings of the present study have been isolated Rhizobium species."