Insect Gut Bacteria: A Novel Source for Siderophore Production

Abstract

Insect gut microbial community is known to produce biotechnologically important products. Present study is focussed on isolation of bacteria and screening of siderophore producing strains of Sathrophyllia femorata collected from Western Ghats region near Pune, Maharashtra, India (19°20′N and 73°47′E). Total 207 bacteria were isolated from gut of 2 different specimens (DM and EM) of grasshopper belonging to S. femorata. Out of 207 bacterial isolates, 166 (79 %) isolates produced siderophore during their submerged growth in iron deficient succinic acid medium. Among these, 24 isolates produced copious amount of siderophore and hence selected for further study. Further analysis of these isolates showed absorption maxima either at 240 or at 250 nm depending on type of siderophore. Molecular identification of these siderophore producing bacteria based on 16S rRNA gene sequencing confirms their affiliation to 37 species representing 19 genera. Dominance of phylum Proteobacteria followed by Firmicutes was observed. Among 19 genera, gammaproteobacteria like Acinetobacter, Klebsiella and Pseudomonas showed abundance over other genera like Serratia, Stenotrophomonas and Yokenella. Some of these bacteria have been used in plant growth promotion and as biocontrol agents against insect pests of plants. Siderophore producing bacteria having insecticidal activity against the insect pests promoting plant growth can serve as green bioinoculants for sustainable agriculture.