The soil biodegradable plastisphere: A hotspot driving microbial shift and antibiotic resistance dissemination

Biodegradable plastics (BPs), as alternatives to conventional plastics, may paradoxically contribute to soil pollution by affecting microbial communities and accelerating antibiotic resistance gene (ARG) dissemination. However, the underlying relationship between BP biodegradation and ARG dissemination remains poorly understood. We conducted a soil microcosm experiment using biodegradable polybutylene adipate- co -terephthalate (PBAT) and polylactic acid (PLA) films. Results showed significant biodegradation of both plastics, with PBAT exhibiting more pronounced weight loss and CO₂ emission than PLA. Metagenomic analysis revealed that distinct bacterial communities and ARG profile assembled on the plastic surfaces, particularly on PBAT, forming a unique plastisphere compared to the surrounding soil. Key genera enriched in the PBAT plastisphere, such as Variovorax , Pseudomonas , and Rhodococcus , as well as Sphingomonas enriched in PLA, were identified as potential BP-degrading bacteria and major hosts of ARGs. Metagenome-assembled genome analysis further indicated that these enriched taxa in the PBAT plastisphere carried abundant ARGs and mobile genetic elements (MGEs), suggesting a higher potential for horizontal gene transfer (HGT) than PLA. Our findings provide new insights into microbial-ARG interactions driven by BPs biodegradation, and provide scientific evidence for a comprehensive assessment of the environmental risks posed by BPs. This insight is critical for developing integrated environmental and public health strategies under the One Health framework. • PBAT degrades faster than PLA in soil but poses greater antibiotic resistance risk. • Key plastic-degrading bacteria are major ARG hosts, particularly in plastisphere. • PBAT plastisphere serves as ARG hotspot, facilitating ARGs transmission to soil. • ARGs co-localize with MEGs and VFs, enhancing horizontal gene transfer risk. • BP biodegradation shapes unique microbiome-ARG interactions in the plastisphere.