Microplastic and lead shift microbiomes enriching viral auxiliary metabolic genes for potential polylactic acid

Xieluyao Wei1, Kinza Bashir1, Xianrui Tian1

  • 1College of Resources, Sichuan Agricultural University, Chengdu, China.

Insights

Biodegradable microplastics and lead co-contamination harm soil health and plant growth. Viruses may play a role in breaking down microplastics in contaminated soils.

Area of Science:

  • Environmental Science
  • Soil Science
  • Microbiology

Background:

  • Biodegradable microplastics (bio-MPs) and heavy metals like lead (Pb) are common soil contaminants.
  • Their combined impact on soil ecosystems, especially viral communities, is poorly understood.

Purpose of the Study:

  • To investigate the effects of polylactic acid (PLA) microplastics, lead, and their combination on buckwheat plants and associated microbial communities.
  • To explore the role of viruses in the co-contamination scenario.

Main Methods:

  • Field study involving buckwheat cultivation under different treatments: PLA, Pb, and combined PLA+Pb.
  • Metagenomic sequencing of soil bacterial and viral communities.
  • Analysis of plant growth, tissue metal accumulation, soil properties, and gene expression.

Main Results:

  • Co-contamination reduced soil pH, nutrient availability, and buckwheat growth, while increasing Pb uptake.
  • Lead-altered bacterial communities, suppressing carbon and phosphorus metabolism genes.
  • Viral communities showed enriched auxiliary metabolic genes (AMGs) for carbon utilization, particularly those hydrolyzing PLA ester bonds.

Conclusions:

  • Combined microplastic and heavy metal contamination poses significant risks to soil health and plant productivity.
  • Viruses may contribute to the degradation of biodegradable microplastics in soil ecosystems.
  • Identification of a specific viral esterase suggests a mechanism for PLA breakdown.

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