Variety-Specific Accumulation of Dibutyl Phthalate in Choysum ( Brassica parachinensis L.) Driven by Rhizosphere Metabolite-Mediated Bacterial Recruitment

Abstract The accumulation of phthalate esters (PAEs) in crops is largely regulated by rhizosphere microorganisms, which are associated with food safety and human health. Currently, the mechanisms underlying the PAE accumulation remain elusive. Here, we revealed the critical roles of rhizosphere metabolite-mediated bacterial recruitment in variety-specific dibutyl phthalate (DBP) accumulation in choysum through integrated microbiome and metabolomic analyses. The DBP low-accumulating variety (LAV) selectively enriched DBP-degrading bacteria (e.g., Sphingobacterium sp.) by secreting a higher relative abundance of thiamine, which enhanced soil DBP dissipation and reduced plant DBP accumulation. In contrast, the high-accumulating variety (HAV) recruited plant growth-promoting bacteria (e.g., Bacillus sp.) by exuding higher relative abundance of luteolin 7-O-glucuronide, resulting in improved plant biomass accompanied by increased DBP accumulation. Chemotaxis assays and cross-inoculation experiments validated the role of root-exudate-dominant rhizosphere metabolites in bacterial recruitment and their functional outcomes on DBP fate in soil-crop systems. The findings provide novel insights into the PAE accumulation in crops in terms of plant–microbial interactions, highlighting a promising strategy to ensure crop safety in PAE-polluted environments by shaping rhizosphere metabolite-driven bacterial assembly.