Microbial inoculants alleviate continuous cropping obstacles in Gynostemma pentaphyllum (Thunb.) Makino by reshaping rhizosphere microbial communities

Gynostemma pentaphyllum (Thunb.) Makino, a Chinese medicinal herb, has long been utilized in traditional medicine for managing various ailments. However, the rapid expansion of its cultivation has led to increasingly prominent continuous cropping obstacles (CCOs), which severely restrict sustainable production. Microbial inoculants have shown effectiveness in mitigating CCOs in crops. In this study, compared with the control group, the dry weight and fresh weight per unit area of G. pentaphyllum were significantly increased by 35.96% and 32.11%, respectively, while the total polysaccharide content was increased by 6.03%. Pot experiments with soil extracts of different pore sizes revealed that microbial inoculants alleviate CCOs in G. pentaphyllum by reshaping microbial communities. Concurrently, Gemmatimonadaceae and Xanthomonadaceae were significantly enriched in the rhizosphere as core microbial taxa, demonstrating antagonistic effects against pathogens, while the abundance of the pathogenic fungus Volutella was markedly reduced. Functional prediction analyses confirmed the enhancement in bacterial antagonistic activity against pathogens and the reduction in fungal pathogenic functions. This study provides a theoretical foundation for developing specialized microbial fertilizers to address CCOs, while also establishing both mechanistic insights and practical strategies for the sustainable development of G. pentaphyllum.