Journal of Pure and Applied MicrobiologyVol. 2 No. 2

Evaluation of Antifungal Activity of Siderophore Produced by Fluorescent Pseudomonas sp. Isolated from Paddy Rhizosphere

R. Hemala Devi, B. Sivasankari and Thilagavathy Daniel

Department of Biology, Gandhigram Rural University, Gandhigram - 624 302, India.

Received on 12 May 2008 and accepted on 08 August 2008



Fluorescent Pseudomonas sp. isolated from paddy rhizosphere was biochemically confirmed and screened for siderophore production. The isolate was able to produce two types of siderophores ie, hydroxamates and catecholates and the production were assayed at different pH and different time intervals. The production of hydroxamate type siderophore was high at pH 8 (246 µg ml-1) and on 3rd day while the production of catecholate type siderophore at pH 7(146 µg ml-1) and on 3rd day. The bacterial isolate and their crude extract of siderophore were screened for antifungal activity against two phytopathogens Fusarium oxysporum and Alternaria sp. and the isolate showed good inhibition against both the pathogens tested. The crude extract ( hydroxamate and catacholate) showed higher inhibition at a concentration of 0.6 ml.

Keywords : Fluorescent Pseudomonas sp. siderophores, antifungal effect.