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Contamination of soil by antibiotics and heavy metals originating from hospital facilities has emerged as a major cause for the development of resistant microbes. We collected soil samples surrounding a hospital effluent and measured the resistance of bacterial isolates against multiple antibiotics and heavy metals. One strain BMCSI 3 was found to be sensitive to all tested antibiotics. However, it was resistant to many heavy metals and metalloids like cadmium, chromium, copper, mercury, arsenic, and others. This strain was motile and potentially spore-forming. Whole-genome shotgun assembly of BMCSI 3 produced 4.95 Mb genome with 4,638 protein-coding genes. The taxonomic and phylogenetic analysis revealed it, to be a Bordetella petrii strain. Multiple genomic islands carrying mobile genetic elements; coding for heavy metal resistant genes, response regulators or transcription factors, transporters, and multi-drug efflux pumps were identified from the genome. A comparative genomic analysis of BMCSI 3 with annotated genomes of other free-living B. petrii revealed the presence of multiple transposable elements and several genes involved in stress response and metabolism. This study provides insights into how genomic reorganization and plasticity results in evolution of heavy metals resistance by acquiring genes from its natural environment.

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The interaction between microbes and plants in rhizospheric environment is evident regarding sustainable development in agriculture. Microbes are involved in various metabolic activities in plant systems, which in turn help in plant health improvement. Eventually, plant-microbe interactions are connected with biogeochemical cycles. In this context, metagenomic study helps us to survey the microbial diversity in their natural niches, especially in rhizospheric regions. Noticeably, a diverse group of bacteria, fungi, and archaea are likely to be involved in plant growth promoting (PGP) activities. Variation in microbial communities in the rhizosphere depends on various parameters, such as soil organic matter, plant genotype, plant exudates, crop rotation, soil pH, nutrient cycling, etc. Some abiotic factors and chemical fertilizers have negative impact on crop productivity, influencing sustainable development of environment. Despite having negative impacts from climate change, microbes cope with this altered scenario and try to adjust themselves successfully and consequently promote plant growth by nutrient acquisition and stress tolerance approaches. Therefore, climate change has appeared as a big threat to the agricultural sector in recent past and this might be persistent in near future. However, the conservation of microbial diversity in the rhizospheric regions appears as one of the most promising options for long-term environmental sustainability.

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