Antimicrobial Activity of Local Rhizobial Isolates Against Some fungi

Abstract

In this study, three isolates of Ensifer fredii bv. fredii were isolated from root nodules of Vigna unguiculata L. (Cowpea) which collected from different cultural areas in Nineveh Governorate/Iraq. The rhizobial colonies were purified and their agronomic and biochemical characteristics were studied. Microscopic examination results showed rod negative Gram stain bacteria, whereas the three isolates showed ability to grow on rhizobial minimal medium (RMM), motility on TY semi-solid medium, gelatin liquefaction, citrate utilization as a sole carbon source, as well as the isolates showed a positive result for Triple Sugar Iron (TSI). Antimicrobial activity study of local rhizobial isolates against fungi showed a clear effect on studied fungi. The filtrate culture of Ensifer fredii bv. fredii ORM1 showed inhibition zone effect with average 12.6, 10.3 and 12.0 mm against Aspergillus niger MR1, Fusarium solani MR2 and Penicillium spp. MR3, respectively, whereas the filtrate culture of Ensifer fredii bv. fredii ORM13 showed inhibition zone effect with average 10.0, 13.3 and 13.0 mm against Aspergillus niger MR1, Fusarium solani MR2 and Penicillium spp. MR3, respectively. A filtrate culture of Ensifer fredii bv. fredii ORM23 showed less effect against each of Aspergillus niger MR1 and Penicillium spp. MR3 which inhibition zone average 8.6 mm, whereas there is no inhibition effect were recorded for culture filtrate against Fusarium solani MR2.