Symbiotic effectiveness and bacteriocin production by Rhizobium leguminosarum bv. viciae isolated from agriculture soils in Faisalabad

Antagonism amongst mixtures of inoculant strains of Rhizobiaceae on the basis of bacteriocin production was assessed. A total number of 10 strains of Rhizobium, Bradyrhizobium and Agrobacterium were screened for their bacteriocin production ability. It was observed that Rhizobium leguminosarum bv. viciae strain LC-31 produced a medium typed bacteriocin that was found to be highly effective in growth inhibition of some strains of R. leguminosarum bv. viciae and Agrobacterium sp. It was isolated and partially purified to homogeneity by chloroform extraction followed by ammonium sulfate fractionation. The bacteriocin fraction consistently migrated as a 50 kDa polypeptide on SDS-PAGE. Ex vivo assays were carried out using the partially purified bacteriocin protein fraction of R. leguminosarum bv. viciae strain LC-31 against related strains of the same species. It showed an activity pattern similar to that exhibited by strain LC-31. (C) 2004 Elsevier B.V. All rights reserved.