They break down the organic and inorganic compounds, and release them back into the environment as metabolic compounds (Gentry et al. Microorganisms are widely present in natural environments. Therefore, soil formation for sustainable growth of plant is the key to solve the problem in long-term maintenance of external-soil spray seeding technology. However, the current spraying material cannot break down rocks to continuously provide essential nutrients for plant growth. Spraying material on the surface of exposed rocks supplemented with plant seeds, soil and nutrients, which is known as external-soil spray seeding technology, is one of the most efficient and highly implemented approaches in the ecological restoration of mining areas (Deng et al. Highly used restoration methods include a combination of these treatments: (a) in situ improvement of the physical and chemical substrate conditions (b) spreading of the healthier soil and top-soiling methods (c) spraying with herbaceous plant species and stabilization of soil and (d) planting of trees and shrubs (Andrés and Mateos 2006). Till date a variety of restoration methods were developed and implemented based on resource availability and ecosystem adaptability. Studies were being conducted to resolve the environmental destruction of these mining sites by developing efficient ecological restoration technologies (Sun et al. The area of soil and water loss in mining sites caused by overexploitation is increasing at a rate of 1.5 × 10 4 km 2 year −1, and more than 20% of these areas have been classified as rocky desertification (Balland-Bolou-Bi and Poszwa 2012). Human encroachments of earth surface in the form of mining have severely destroyed the ecology of the mining areas, causing soil erosion, exposure of bedrock and loss of productivity (Comino et al. Graphical AbstractĪbout 90% of the earth crust is composed of silicate minerals and these silicates are building blocks of most rock types (Wang et al. Our study reports a potential bacterial based approach for improving the ecological restoration of over-exploited rock mining sites. Specifically, 15 differentially expressed genes (DEGs) encoding for siderophore transport, EPS and amino acids synthesis, organic acids metabolism, and bacterial resistance to adverse environmental conditions were highly up-regulated in silicate rock cultures of NLX-4 strain. Through employing genome and transcriptome sequencing (RNA-seq), we identified the major regulatory genes.
NLX-4 strain efficiently accelerates the dissolution of silicate rocks by secreting amino acids, exopolysaccharides, and organic acids. The results revealed that Pseudomonas sp. NLX-4 strain isolated from an over-exploited mining site.
In this study, we performed silicate rock-dissolution experiments on a Pseudomonas sp. However, our understanding of the molecular mechanisms involved during bacterial rock-dissolution is still limited. Some soil-inhabiting bacteria exhibit efficient rock-dissolution abilities by releasing organic acids and other chemical elements from the silicate rocks. Microbial weathering processes can significantly promote soil properties and reduce rock-to-soil ratio.
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