title: Soybean plants modify metal oxide nanoparticle effects on soil bacterial communities.
abstract: Engineered nanoparticles (ENPs) are entering agricultural soils through land application of nanocontaining biosolids and agrochemicals. The potential adverse effects of ENPs have been studied on food crops and soil bacterial communities separately; however, how ENPs will affect the interacting plant-soil system remains unknown. To address this, we assessed ENP effects on soil microbial communities in soybean-planted, versus unplanted, mesocosms exposed to different doses of nano-CeO2 (0-1.0 g kg(-1)) or nano-ZnO (0-0.5 g kg(-1)). Nano-CeO2 did not affect soil bacterial communities in unplanted soils, but 0.1 g kg(-1) nano-CeO2 altered soil bacterial communities in planted soils, indicating that plants interactively promote nano-CeO2 effects in soil, possibly due to belowground C shifts since plant growth was impacted. Nano-ZnO at 0.5 g kg(-1) significantly altered soil bacterial communities, increasing some (e.g., Rhizobium and Sphingomonas) but decreasing other (e.g., Ensifer, Rhodospirillaceae, Clostridium, and Azotobacter) operational taxonomic units (OTUs). Fewer OTUs decreased from nano-ZnO exposure in planted (41) versus unplanted (85) soils, suggesting that plants ameliorate nano-ZnO effects. Taken together, plants--potentially through their effects on belowground biogeochemistry--could either promote (i.e., for the 0.1 g kg(-1) nano-CeO2 treatment) or limit (i.e., for the 0.5 g kg(-1) nano-ZnO treatment) ENP effects on soil bacterial communities.
authors.affiliation: Bren School of Environmental Science and Management, ‡Earth Research Institute, §University of California Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California , Santa Barbara, California 93106, United States.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Ge
authors.forename: John H
authors.initials: JH
authors.lastname: Priester
authors.forename: Laurie C
authors.initials: LC
authors.lastname: Van De Werfhorst
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Walker
authors.forename: Roger M
authors.initials: RM
authors.lastname: Nisbet
authors.forename: Youn-Joo
authors.initials: YJ
authors.lastname: An
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Schimel
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Gardea-Torresdey
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Holden
mesh_terms: D001419:Bacteria / Q000187:drug effects*; D002563:Cerium / Q000494:pharmacology*; D053768:Metal Nanoparticles / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000494:pharmacology; D013025:Glycine max / Q000378:metabolism*; D015034:Zinc Oxide / Q000009:adverse effects* / Q000494:pharmacology*
chemical_list: D012989:Soil Pollutants; D002563:Cerium; C030583:ceric oxide; D015034:Zinc Oxide