Microbial Community Dynamics and Rice Adaptation in Saline–Alkali Soils: Insights into Plant-Microbe Interactions

The saline–alkali soil environment profoundly influences the diversity and composition of soil microbial communities, reshaping their ecological network structures. As a vital staple crop, rice (Oryza sativa L.) plays a crucial role in global food security, highlighting the urgent need to improve its cultivation efficiency in saline–alkali soils. However, the mechanisms by which rice roots recruit beneficial microorganisms from native soils under prolonged saline–alkali stress remain largely unclear, and limited research has been conducted on the effectiveness of microbial inoculants in enhancing rice salt tolerance. This study investigated microbial communities in a saline field subjected to over a decade of continuous rice cultivation. Plant growth-promoting microorganisms were isolated and screened from the rhizosphere. The findings revealed long-term salt stress significantly altered microbial diversity and community composition, although the overall microbial network structure remained resilient. A total of 21 plant growth-promoting strains were identified, indicating that rice roots under sustained salt stress selectively recruit beneficial microbes that contribute to plant growth and stress adaptation. Further experimental validation demonstrated that synthetic microbial communities outperformed individual strains in promoting rice seedling growth under high-salinity conditions, likely due to synergistic microbe and microbe–plant interactions. In conclusion, while saline–alkali conditions disrupt native microbial communities, rice exhibits adaptive capacity by selectively enriching growth-promoting microorganisms. The application of synthetic microbial consortia presents a promising strategy to enhance rice resilience and productivity in saline–alkali environments.