Research Progress on the Role and Application of Plant Growth-Promoting Rhizobacteria in the Formation and Stabilization of Soil Organic Matter in Mined land

Mining activities have caused severe degradation of natural soils in mining areas, characterized by organic matter depletion, structural damage, and heavy metal contamination, posing significant challenges for ecological restoration. A key challenging in restoring these soils lies in the low level of soil organic matter and the unclear mechanisms underlying its stabilization, particularly the microbially driven processes of carbon transformation and stabilization. Plant Growth-Promoting Rhizobacteria (PGPR), as functional microorganisms, have shown great potential in promoting plant growth, enhancing soil organic matter (SOM) accumulation, and facilitating ecological restoration in mining areas. This review systematically summarizes the functional types of PGPR and the main factors influencing their survival and performance in mining soils. The review further highlights the pathways and mechanisms of PGPR mediated SOM formation and stabilization, including: promoting plant-derived carbon input, modulating microbial carbon metabolism, enhancing the accumulation of microbial derived OM, and facilitating the formation of organo-mineral association and soil aggregate structures. Furthermore, the review discusses the prospective applications of PGPR in mined land restoration and carbon sequestration - organic matter sequestration, such as the development of single-strain inoculants, construction of synthetic microbial consortia, combined application with organic-inorganic amendments, and the use of artificial intelligence to assist in strain selection. Overall, this review provides theoretical and technical support for establishing PGPR-based, green, and sustainable ecological restoration strategies in mining areas, thereby contributing to the reconstruction of mining ecosystem functions.