Rhizosphere microbiomes as nature-based solutions for saline soil rehabilitation: a synthesis of mechanisms, multi-omics insights, and rice-Brassica rotation strategies

Soil salinization threatens global agriculture by reducing crop yields, altering microbial diversity, and disrupting ecosystem functions. Rice (Oryza sativa) is particularly sensitive to salt stress yet is widely grown in saline reclamation areas. Rhizosphere microbiomes can support plant resilience through nutrient cycling, osmotic regulation, pathogen suppression, and biofilm formation. Under elevated salinity, these communities often shift toward salt-tolerant taxa (Proteobacteria, Actinobacteria, Bacteroidota) linked to ion homeostasis and nutrient acquisition, although the functional consequences remain context-dependent. Crop rotations with salt-tolerant root vegetables such as turnip (Brassica rapa) are conceptually attractive for rehabilitating saline soils by reshaping microbial communities, improving soil structure, and suppressing certain pathogens. Direct evidence for consistent benefits in saline rice systems is still limited. Rotation-induced microbial and physical changes may, under favorable conditions, leave a legacy that supports subsequent rice crops. This review synthesizes current knowledge and proposes a conceptual framework linking microbial dynamics, plant responses, and soil-property changes under salinity. We highlight the potential of multi-omics approaches and microbiome-based interventions while underscoring key gaps: scarce long-term field validation, uncertain persistence of microbial legacies, and limited economic assessment. Treating saline soils as systems in which microbiome processes play a central role offers a foundation for more sustainable strategies, provided these are rigorously validated in the field. Rhizosphere microbiome-mediated saline soil rehabilitation through rice–turnip rotation.