Impact of TiO₂ and ZnO Nanoparticles on Soil Bacteria and the Enantioselective Transformation of Racemic-Metalaxyl in Agricultural Soil with Lolium perenne: A Wild Greenhouse Cultivation

Abstract

The effects of TiO2 and ZnO nanoparticles on soil bacteria and enantioselective transformation of racemic-metalaxyl (rac-metalaxyl) in agricultural soil with or without Lolium perenne were investigated in an outdoor greenhouse. After a 70-day exposure to 2‰ ZnO, microbial biomass carbon decreased by 66% and bacterial community composition significantly changed. Meanwhile, ZnO decreased chlorophyll cumulation in L. perenne by 34%. ZnO also inhibited the enantioselective transformation of metalaxyl enantiomers and changed the enantiomer fraction of metalaxyl. TiO2 showed similar effects but to a lesser extent. L. perenne promoted the transformation of rac-metalaxyl and ingested TiO2 and ZnO. L. perenne changed the bacterial co-occurrence networks and biomarkers in native soil and soil exposed to TiO2 and ZnO. L. perenne reduced the inhibition effects of TiO2 and ZnO on the transformation of rac-metalaxyl. The decrease in the relative abundance of soil keystone taxa such as Acidobacteria and Gemmatimonas might respond to the corresponding slow transformation of rac-metalaxyl in soils exposed to TiO2 and ZnO, regardless of L. perenne. Our results demonstrated the existence of mutual interactions among the impact of engineered nanoparticles on different components (microbes, plants, and coexisting pollutants) in the terrestrial ecosystem.

Bioinspired Green Synthesis of Zinc Oxide Nanoparticles from a Native Bacillus cereus Strain RNT6: Characterization and Antibacterial Activity against Rice Panicle Blight Pathogens Burkholderia glumae and B. gladioli

“…Conversely, some studies reported the adverse effects of chemically produced ZnONPs on plant soil microbial communities [26,27]. Another study performed by Zhou et al [28] showed the adverse impact of chemically produced ZnONPs on soil microorganism biomass and racmetalaxyl transformation. However, microbe-based synthesis of ZnONPs has enormous potential benefits in terms of long-term stability, nontoxicity, eco-friendliness, and ease of scaling-up as compared to those NPs fabricated via chemical and physical methods [22].…”

Enantioselective Behaviors of Chiral Pesticides and Enantiomeric Signatures in Foods and the Environment

“…Preferential enrichment of R -quizalofop-ethyl in soil amended with biosolids was found; however, no enantioselectivity occurred when soil was amended with biosolids containing ZnO . Similarly, the presence of ZnO or TiO 2 nanoparticles inhibited the enantioselective dissipation of metalaxyl in soil . However, the coexistence of oxytetracycline had very limited influence on the enantioselective degradation of beta-cypermethrin in soil .…”

“…79 Similarly, the presence of ZnO or TiO 2 nanoparticles inhibited the enantioselective dissipation of metalaxyl in soil. 80 However, the coexistence of oxytetracycline had very limited influence on the enantioselective degradation of beta-cypermethrin in soil. 81 The presence of norfloxacin had no effect on the enantioselectivity of acetochlor in sediment.…”

Uso de nanomateriales en la agricultura y sus implicaciones ecológicas y ambientales

“…El contacto de NMs en cultivos microbianos puros demostró tener efectos inhibitorios en el crecimiento de rizobacterias promotoras del crecimiento (PGPR, por sus siglas en inglés) además de otras bacterias involucradas en el ciclo del N (Ameen et al, 2021). En otro estudio se demostró que las NPs de óxidos metálicos tales como TiO 2 y ZnO, usadas en el sector agrícola como agentes antimicrobianos y fertilizantes, causaron la reducción de la biomasa microbiana (BM), medida como C orgánico presente en la biomasa (C-BM), especialmente el proveniente de bacterias Gram (-) (Zhou et al, 2020). Otros estudios han recurrido a la evaluación del efecto de NMs sobre suelo directamente, por ejemplo, empleando NPs de TiO 2 y ZnO a diferentes concentraciones durante 60 días (Ge et al, 2011); el estudio indicó que las NPs redujeron significativamente la concentración de C-BM; concluyendo que esta reducción se vio reflejada como la disminución de la actividad microbiana y enzimática, así como a la modificación de la estructura poblacional.…”