Isolation and Characterization of ِLocal strains of Rhizobium leguminosarum bv. trifolii

Salim Qasim, Wjdan

	Isolation and Characterization of ِLocal strains of Rhizobium leguminosarum bv. trifolii "
Tikrit Journal of Pure Science
Article 1, Volume 16, Issue 4, 2011, Pages 23-27
Author
Wjdan Salim Qasim
Abstract
This study included isolation and characterization of seven strains of Rhizobium leguminosarum bv. Trifolii from root nodules of clover plants. These strains as follows: WS1, WS2, WS3, WS4, WS5, WS6 and WS7. Clover plants were isolated from different agroclimatic regions of Mosul-Iraq. Symbiotic characteristics of clover plants inoculated with the fore-isolated strains of rhizobia revealed that the strain WS4 was the best, which has the symbiotic efficiency 15.6. This strain had been chosen for further studies; such as the effect of different incubation periods on growth of WS4 strain and pH changes of MSY medium. Three-day after incubation was the best with average optical density 1.83, when wavelength was 545 nm. Intensive incubation period resulted in decreasing the average values of optical density. Antibiotic resistant studies showed the ability of strains in resisting chloramphenicol, rifampicin, streptomycin, ampicillin and naldixic acid, whereas it was sensitive to tetracycline. The strain WS4 was able to grow on RMM. Study of production of cell surface molecules revealed disability of this strain to produce β (1 3) cyclic glucans, whereas it had the ability to produce the exopolysaccharide and cellulose fibrilis. SW4 was motile, this indicating its ability to produce β-(1 2) cyclic glucans.

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Isolation and Characterization of ِLocal strains of Rhizobium leguminosarum bv. trifolii "