Microplastic particles alter wheat rhizosphere soil microbial community composition and function.

Area of Science:

• Environmental Science
• Soil Science
• Microbiology

Background:

• Microplastics (MPs) are widespread in terrestrial ecosystems, potentially altering soil properties and processes.
• The specific impacts of different MP types on soil bacterial communities, particularly in the rhizosphere, are not well understood.

Purpose of the Study:

• To investigate the effects of three common microplastic types—polyethylene (PE), polyvinylchloride (PVC), and polystyrene (PS)—on the structure and function of rhizosphere soil bacterial communities.
• To compare the distinct impacts of PE, PVC, and PS microplastics on soil microbial alpha diversity and functional gene profiles.

Main Methods:

• Three microplastic types (PE, PVC, PS) of uniform size (200 µm) and concentration (2%) were introduced into soil.
• Rhizosphere soil bacterial community structure was analyzed using diversity indices.
• Functional potential of bacterial communities was predicted using PICRUSt2 analysis.

Main Results:

• Microplastics generally decreased microbial alpha diversity (richness, evenness, diversity), with PE MPs showing the most significant reduction.
• The relative abundance of bacterial phyla and genera involved in pollution degradation increased, suggesting varied biodegradation pathways influenced by MP type.
• Polystyrene (PS) decreased functional categories and bacterial genus numbers, while polyethylene (PE) and polyvinylchloride (PVC) enhanced metabolic pathways and xenobiotic biodegradation.

Conclusions:

• Different microplastic types exert distinct influences on the structure and function of soil bacterial communities in the rhizosphere.
• Understanding these varied impacts is crucial for assessing the ecological risks of microplastic pollution in terrestrial environments.
• Findings highlight the need to consider MP characteristics when evaluating their effects on soil microbial ecosystems and functions.