Isolation, identification and functional characterisation of bacteria associated with gut of wood feeding Stromatium barbatum (Fabr.) (Coleoptera: Cerambycidae) larvae

Gut of the insect is associated with different types of bacteria. Information on the symbiotic association of bacteria with the insect is important to understand the different physiological process which can be used in developing strategies for insect inhibition. This approach requires proper understanding of symbiotic bacteria associated with the insect gut. In this study, twenty-five bacteria were isolated from the foregut, midgut and hindgut region of S. barbatum by culture dependent method. They were identified by 16S rRNA gene sequencing. Molecular and phenotypic analysis of the isolates confirmed the affiliation of bacteria to phylum Firmicutes, Proteobacteria and Actinobacteria. Gram positive bacteria dominated the gut region. Bacteria belonging to genus Bacillus, Staphylococcus, Enterobacter, Pseudomonas, Enterococcus, Ochrobactrum, Brachybacterium, Microbacterium, Rhodococcus and Leucobacter were identified from the gut region. Proteolytic activity was exhibited by most bacteria followed by amylase, cellulase, pectinase and lipase. This preliminary information of culturable bacterial community of insect gut would contribute to our existing knowledge of microbes associated with S. barbatum which would in turn help in formulating strategies for control of this pest. Stromatium barbatum (Fabr.) (Coleoptera: Cerambycidae) larvae causes damage to the crop by feeding inside the stem which ultimately results in drying of stem. Because of their presence inside the wood, chemical pesticides are unable to inhibit the insect resulting in major crop damage. Therefore, an alternative safe way is needed to prevent the grapevine infestation by S. barbatum.