Continuous cropping of Strobilanthes sarcorrhiza drives rhizosphere bacterial community dysbiosis and growth differentiation

Background and aims Strobilanthes sarcorrhiza is a medicinal and edible plant of high economic value, yet its sustainable cultivation is severely constrained by continuous cropping, which reduces yield and quality. Unraveling the ecological mechanisms behind these obstacles is critical for developing effective mitigation strategies. Methods We integrated agronomic trait evaluation, soil physicochemical profiling, and 16S rRNA–based microbial community analysis to characterize rhizosphere ecological succession across successive years of S. sarcorrhiza monoculture. Results Continuous cropping obstacles progressively acidified soils and disrupted nutrient balance, with accumulation of soil carbon–nitrogen pools, ammonium enrichment, and nitrate depletion. Rhizosphere bacterial diversity, evenness, and richness declined, accompanied by intensified β-diversity. Functional prediction revealed enrichment of chemoheterotrophic taxa but loss of nitrogen-fixing and cellulose-degrading capacities. Network analysis showed a collapse of cooperative interactions, replaced by antagonistic competition. Notably, beneficial Streptomyces sharply declined, while pathogenic Ralstonia and nematode symbionts ( Xiphinematobacter) proliferated. Conclusions Continuous cropping impairs the rhizosphere soil health of S. sarcorrhiza by causing nutrient imbalances, reducing microbial diversity, and increasing pathogens, which negatively impacts its growth. These findings offer a theoretical basis for addressing continuous cropping challenges in agriculture.