Reprogramming of microbial community in barley root endosphere and rhizosphere soil by polystyrene plastics with different particle sizes

Polystyrene plastics is an emerging pollutant affecting plant performance and soil functioning. However, little informa-tion is available on the effects of microplastics and nanoplastics on plant root endophytic and rhizospheric soil micro-bial communities. Here, barley plants were grown in microplastics/nanoplastics -treated soil and the diversity, composition and function of bacteria and fungi in the root and rhizosphere soil were examined. At the seedling stage, greater changes of root endophytes were found compared with rhizosphere microorganisms under the plastic treatments. Nanoplastics decreased the richness and diversity of the fungal community, while microplastics increased the diversity of the root endophytic bacterial community. The network of the bacterial community under nanoplastics showed higher vulnerability while lower complexity than that under the control. However, the bacterial community under microplastics had a relatively higher resistance than the control. For the rhizosphere microbial community, no significant effect of plastics was found on the alpha-diversity index at the seedling stage. In addition, the nanoplastics resulted in higher sensitivity in the relative abundance and function of rhizosphere soil microbes than root endophytic microbes at the mature stage. Treatments of polystyrene plastics with different particle sizes reprogramed the rhizo-sphere and root endophytic microbial communities. Different effects of microplastics and nanoplastics were found on the diversity, composition, network structure and function of bacteria and fungi, which might be dueto the varia-tion in particle sizes. These results lay a foundation for learning the effects of polystyrene plastics with different particle sizes on the microorganisms in rhizosphere soil and plant roots, which may have important implications for the adap-tation of plant-microbial holobiont in polystyrene plastics-polluted soils.

Automated summary

Little information is available on the effects of microplastics and nanoplastics on plant root endophytic and rhizospheric soil microbial communities. This study found that microplastics and nanoplastics treatments had different effects on the diversity, composition, network structure, and function of bacteria and fungi in barley plants, providing important insights into the impact of plastics on rhizospheric soil microorganisms.