Development of a Novel Consortium Using Bacteria With Multiple Plant Beneficial Traits From Over-Exploited Agricultural Soil

Soil is a treasure trove of myriad microbial communities that encompass a bewildering array of physiological, metabolic, and genomic diversity essential for sustenance of soil fertility. Over-exploitation of arable lands with extensive use of agrochemicals has negatively impacted soil structure and function by lowering crop productivity. Such damaged agro-ecosystem can be recovered through restoration of microbial richness to replenish various plant-beneficial services at community level. Incorporation of potential single or multiple plant-growth promoting bacteria (PGPB) in soil is a unique strategy in modern sustainable agriculture. In this study, PGPB strains were isolated from a long-term used agricultural soil of Bahadurpur, West Bengal. Only the bacterial isolates having nitrogen, phosphorus and potassium acquisition ability were further screened for multiple plant growth promoting (PGP) traits. Isolates S3, S5, and R1 showed nitrogen-fixing, phosphate and potassium solubilizing ability. They were tested for production of IAA, GA, ACC deaminase, siderophore, biofilm, lytic enzymes, and volatile biochemical compounds under in vitro condition. Three most potent isolates (S3, S5 and R1) were selected for development of a multi-strain consortium to be utilized as bio-inoculant. Based on 16s rRNA gene sequence they were identified as Bacillus zhangzhouensis strain MMAM, B. cereus strain MMAM3, and B. subtilis strain MMAM2.