Alfalfa (Medicago sativa L.) is a crucial plant for saline and alkaline soil development, which is crucial for managing the salinization of global land resources. It can withstand saline and alkaline stress and can fix nitrogen. By secreting phytohormones, fixing nitrogen, and boosting antioxidant capacity, nitrogen–fixing bacteria, rhizobacteria, and other inter–root biotrophic bacteria encourage alfalfa development and reduce salinity stress. Alfalfa’s symbiotic association also encourages other plants to tolerate salinity and greatly boosts the amount of nitrogen in the soil. The mechanism by which inter–root growth–promoting bacteria mitigate saline and alkaline stress in alfalfa remains a prominent research focus. This paper reviews the current state of research on inter–root probiotic bacteria associated with alfalfa, utilizing literature mining to summarize the resource information of inter–root nitrogen–fixing bacteria found in saline–alkaline soils. We elucidate their nitrogen-fixing mechanisms and adaptive characteristics, explore their roles and potential applications in the improvement of saline–alkaline lands, and provide a theoretical foundation for the development of novel nitrogen–fixing bacterial fertilizers and restoration technologies for saline–alkaline environments.

As the primary cash crop for natural fiber, cotton develops under sophisticated endogenous genetic programs, with biotic and abiotic stresses continuously driving its adaptive evolution. MicroRNAs (miRNAs) are post-transcriptional regulators that modulate gene expression via target mRNA cleavage, translational repression, and mediation of DNA methylation. miRNAs target transcription factors and hormone signaling pathways to regulate cotton plant architecture and fiber development. In addition, miRNAs mitigate biotic and abiotic stresses through ROS, lignin, and hormone pathways, as well as by forming competing endogenous RNA (ceRNA) modules with long noncoding RNAs (lncRNAs). This review establishes an miRNA-centered regulatory framework that coordinates cotton growth, development, and stress resistance. A series of technologies, including multi-omics combined with machine learning, gene overexpression, STTM, MIM, MIGS, CRISPR editing, foliar dsRNA spraying, and bionanocarriers, are proposed to facilitate the breeding of cotton varieties with high yield, superior fiber quality, and broad-spectrum stress tolerance.