Production of Bacillibactin Siderophore from Soil Bacteria, Bacillus subtilis: A Bioinoculant Enhances Plant Growth in Arachis hypogaea L. Through Elevated Uptake of Nutrients

Siderophores are iron chelator low molecular weight secondary metabolite produced by microorganisms found in limited iron environment. In this study, a bacterium capable of secreting siderophores was isolated from the iron deficiency rhizosphere agriculture soil from Salem district, Tamil Nadu, India. The isolate was identified as Bacillus subtilis (LSBS2) based on biochemical characteristics and 16S rRNA gene sequences analysis. The siderophores production ability of the strain was evaluated qualitatively and quantitatively through Chrome Azural S assay. The TLC analysis of the LSBS2extract developed brown colour spots indicating catacholate type of siderosphore of isolate had the ability to produce 20 mg L -1 of siderophores in liquid medium. Further, the siderophores was partially purified and identified as bacillibactin type using HPLC, FTIR and the bacillibactin structure was confirmed by 2D-NMR analysis. Furthermore, a field experiment was conducted with Arachis hypogaea to assess the inoculation effect of LSBS2 on plant growth and other physico-chemical parameters. Inoculation of LSBS2 increased plant biomass, pigment content, nutrients, Iron content and oil content than the uninoculated control. The present result suggested that the occurrence of bacillibactin type siderophores in strain LSBS2 play a key role in iron chelation and favors the healthy growth of Sesamum indicum . Therefore, the strain LSBS2 could be exploited as a potential bioinoculant for stimulating peanut plant immunity.