Continuous Cropping Reshapes the Rhizosphere Microbiome and Soil Properties in Tobacco Production Systems

ABSTRACT Continuous cropping obstacles (CCOs) severely constrain tobacco yield and quality, yet the mechanisms by which they influence rhizosphere microbial communities remain poorly understood. This study investigated the predominant tobacco cultivar K326 in Yunnan Province to elucidate soil–microbe interactions under CCOs. We examined how CCOs shape rhizosphere environments and microbial dynamics by integrating soil chemical analyses with molecular ecological techniques. The CC led to significant alterations in soil properties, including declines in pH, organic matter (OM), organic carbon (OC), and total nitrogen (TN), along with variable trends in available phosphorus (AP), potassium (AK), and ammonium (NH 4 + ‐N). The composition of water‐stable aggregates also shifted notably with cropping duration. Bacterial alpha diversity increased progressively with CC, whereas fungal diversity peaked early and declined thereafter. Constrained principal coordinate analysis (CPCoA) revealed distinct clustering among treatments, with fungal communities showing greater sensitivity to CCO‐induced stress. Taxonomic analysis revealed a decreases in Bacteroidota but an enrichments of Gemmatimonadota and Planctomycetota, accompanied by reductions in beneficial bacterial genera, including Streptomyces and Sphingomonas. In contrast, fungal communities exhibited declines in Dothideomycetes and Alternaria, while Sordariomycetes and Penicillium became more dominant. Co‐occurrence network analysis showed that microbial interactions and network complexity initially strengthened under short‐term CC but weakened with prolonged cultivation, suggesting a gradual restructuring of community stability. Functional predictions further indicated that, although nutrient cycling potential was initially higher in non‐cropped soils, processes such as nitrification, cellulolysis, and saprotrophic activity were progressively enhanced under CC. These findings deepen our understanding of rhizosphere ecological responses to CCOs and provide a theoretical basis for microbiome‐informed nutrient management strategies to sustain tobacco productivity over the long term.