Microbial communities on biodegradable plastics under different fertilization practices in farmland soil microcosms

Plastic mulching is a common practice in agricultural systems and is often combined with fertilization. Biodegradable plastics (BPs) are becoming an alternative to non-biodegradable plastics (non-BPs) for soil mulching. However, the effects of fertilization on the microbial communities on BPs remain unclear. Here, we explored the responses of the plastisphere to different fertilization practices in soil-based microcosms containing three BPs: polylactic acid (PLA), poly (butylene succinate) (PBS), and poly (butylene-adipate-co-terephthalate) (PBAT), and one non-BP (low-density polyethylene, LDPE). The 16S and ITS rRNA gene-based Illumina sequencing method were used to identify the bacterial and fungal communities on the plastics and in the soils. Microbial community structure on BPs was significantly different from that in soils and on LDPE. The predicted functional profiles of bacteria on BPs, especially PBAT, were distinct from those in soils. The plastisphere communities on BPs were dominated by microbes adapted to access and utilize carbon sources compared with of the communities on LDPE. Application of manure increased the alpha diversity of bacterial communities on BPs but decreased it on LDPE. The structure of bacterial communities on BPs changed with the application of manure. Our research establishes the baseline dynamics of plastisphere communities on BPs in soils.