The Reorganization of Rice Rhizosphere Microbial Communities Driven by Nitrogen Utilization Efficiency and the Regulatory Mechanism of Soil Nitrogen Cycling

Nitrogen use efficiency (NUE) in rice cultivation is a key determinant of sustainable agriculture, yet the interaction between NUE and the dynamics of rhizosphere soil microbial communities remain poorly understood. In this study, the changes in rhizosphere soil microbial community composition and function due to NUE were analyzed in six rice genotypes across six treatments. Through 16S rRNA/ITS amplicon sequencing, it was found that rice with different NUEs reshaped the rhizosphere soil microbial community structure, but did not significantly alter the α-diversity of the bacterial community. There was a notable difference in the average abundance of the fungus Arnium in the rhizosphere soil of high-NUE rice compared to low-NUE rice, with a 222.2% increase in the former. Correlation analysis indicated that in high-NUE rice, soil nitrate and nitrite contents drove changes in the fungal community, while in low-NUE rice, soil water-soluble nitrogen and total potassium contents were the key influencing factors for changes in the fungal and nitrogen-fixing bacterial communities, respectively. The findings of this study demonstrate a link between NUE-induced changes in the rhizosphere soil microbiome and nitrogen cycling in rice, providing a basis for targeted nitrogen fertilizer management approaches guided by microbial control.