ISOLATION, IDENTIFICATION AND ANTIMICROBIAL ACTIVITY OF PSEUDOMONADS ISOLATED FROM THE RHIZOSPHERE OF POTATOES GROWING IN ALGERIA

摘要: Fourteen bacterial isolates from the rhizosphere of potato plants growing near Setif, (Algeria) were characterised as fluorescent Pseudomonads by phenotypical methods and one was identified Pseudomonas chlororaphis sequencing ribosomal DNA. In dual culture, this isolate inhibited growth phytopathogenic fungi Fusarium oxysporum f. sp. lycopersici, F. albedinis, solani Rhizoctonia oomycete Pythium ultimum. Extracts supernatants liquid cultures Ps. completely these organisms when incorporated into dextrose agar at a rate equivalent to 0.31 ml culture filtrate/ml, or greater. disc assay, extracts supernatant gave inhibition zones 15 mm 25 for Gram-positive bacteria Bacillus subtilis Paracoccus paratrophus, respectively. Fractionation TLC HPLC with diode array detection allowed identification phenazine carboxylic acid antimicrobial compounds tentative two others 2-hydroxy phenazine.