Root exudate-mediated assemblage of rhizo-microbiome enhances Fusarium wilt suppression in chrysanthemum.

Intercropping is emerging as a sustainable strategy to manage soil-borne diseases, yet the underlying mechanisms remain largely elusive. Here, we investigated how intercropping chrysanthemum (Chrysanthemum morifolium) with ginger (Zingiber officinale) suppressed Fusarium wilt and influenced the associated rhizo-microbiome. Chrysanthemum plants in intercropping systems exhibited a marked reduction in wilt severity and greater biomass compared to those grown in monoculture. In contrast, soil sterilization intensified wilt severity and abrogated the benefits of intercropping, highlighting the critical role of soil microbiota. 16S rRNA gene amplicon analysis revealed that intercropping significantly changed the composition and structure of rhizo-bacterial communities, particularly enriching Burkholderia species, which were closely associated with plant growth and disease resistance. Further investigation demonstrated that ginger root exudates, including sinapyl alcohol and 6-gingerol, greatly promoted the proliferation and colonization of Burkholderia sp. in chrysanthemum rhizosphere, conferring the enhanced disease suppression. Metabolomic profiling revealed that ginger root exudates stimulated the release of specific metabolites by chrysanthemum roots, which promoted the growth and biofilm formation of Burkholderia sp. Our findings uncovered the mechanism by which intercropping chrysanthemum with ginger plants modulated the rhizo-microbiome and thereby resulted in the enhanced disease suppression, offering insights into optimizing plant-microbe interactions for improving crop health and productivity.