Characterization of siderophore produced by Pseudomonas sp. MT and its antagonist activity against Fusarium oxysporum f. sp. cubense and F. oxysporium f. sp. ciceris

Siderophores are low molecular weight iron scavengers produced by bacteria to combat iron stress and also suppress deleterious rhizobacteria. In the present study, microbes were isolated from wheat and tobacco farm in Changa village, Anand district, India, and were screened for their siderophore production. Out of 11 isolates, 6 were siderophore producers as they produced orange halos on CAS agar. Isolated bacteria were examined for their hydroxamate, catechol, and carboxylate type of siderophore, and it revealed that all produced hydroxamate siderophore. Among all the isolates, a potential bacterium was selected for further studies and identified by the biochemical test as Pseudomonas sp. MT. Temporal effect on growth and siderophore production revealed that both were higher at 24 hrs of incubation and remained active up to 8 days and then after the decline. Siderophore was partially purified and chemically characterized by FTIR. A particle size analyzer measured the particle size of the siderophore and showed 91.36 nm in size. The siderophore producer and non-producer were examined for their ability to uptake iron by providing external siderophores, which gave positive results. The isolated bacterium was tested for its antagonistic activity against Fusarium oxysporum f. sp. cubense and F. oxysporium f. sp. ciceris, resulting in inhibition of both the species. Hence, Pseudomonas sp. MT can be effectively used to control Fusarium spp.