Soybean plants modify metal oxide nanoparticle effects on soil bacterial communities

Area of Science:

• Environmental Science
• Soil Science
• Microbiology

Background:

• Engineered nanoparticles (ENPs) are increasingly present in agricultural soils via biosolids and agrochemicals.
• Previous studies examined ENP effects on crops and soil bacteria separately, but the combined plant-soil system response is unknown.

Purpose of the Study:

• To investigate the interactive effects of engineered nanoparticles (ENPs) on soil microbial communities within a plant-soil system.
• To assess how soybean plants influence the impact of nano-cerium oxide (nano-CeO2) and nano-zinc oxide (nano-ZnO) on soil bacterial communities.

Main Methods:

• Mesocosms with and without soybean plants were exposed to varying doses of nano-CeO2 and nano-ZnO.
• Soil bacterial communities were analyzed using operational taxonomic units (OTUs) to determine nanoparticle effects.

Main Results:

• Nano-CeO2 at 0.1 g kg(-1) altered bacterial communities in planted soils, but not unplanted soils, suggesting plant-mediated promotion.
• Nano-ZnO at 0.5 g kg(-1) altered bacterial communities, with fewer OTUs affected in planted soils, indicating plant-mediated amelioration.
• Plants influenced the direction and magnitude of ENP effects on soil bacterial communities, depending on the nanoparticle type and dose.

Conclusions:

• Plant presence significantly modifies the impact of ENPs on soil bacterial communities.
• Plants can either exacerbate (nano-CeO2) or mitigate (nano-ZnO) ENP toxicity in soils, likely through belowground biogeochemical interactions.
• Understanding these plant-soil-nanoparticle interactions is crucial for assessing the ecological risks of ENPs in agriculture.