Phthalate Pollution and Its Induced Oxidative Stress in the Root–Soil Interface Altering Maize Root-Associated Microbiomes

Abstract Phthalate (PAE) residues adversely affect the root-associated microbiome and growth of plants. However, the pollution-driven alteration in root-associated microbiota and the potential effect factors remain elusive. Here, we systematically investigated the toxic impacts of PAEs on the bacterial communities along the bulk soil–rhizosphere–rhizoplane continuum of maize. PAE pollution caused stronger impacts on root-associated bacterial communities and a more significant reduction of diversities and compositional disturbance than those in bulk soil. Differential ecological assembly patterns and lower interactive stability of root-associated bacterial communities suggested their dysbiosis and weak adaptation against PAE pollution compared with bulk soil. Transcriptome analysis revealed significant downregulation of the reactive oxygen species (ROS) metabolism function in roots under PAE stress. Upon PAE impacts, significant ROS elevation occurred at the root–soil interface, which significantly shifted the soil bacterial community and inhibited specific species (e.g., Devosia). These findings highlight PAE pollution and its induced oxidative stress in the root–soil interface, impacting the root-associated microbiome.