title: Arbuscular mycorrhizae alleviate negative effects of zinc oxide nanoparticle and zinc accumulation in maize plants--A soil microcosm experiment.
abstract: ZnO nanoparticles (NPs) are considered an emerging contaminant when in high concentration, and their effects on crops and soil microorganisms pose new concerns and challenges. Arbuscular mycorrhizal (AM) fungi (AMF) form mutualistic symbioses with most vascular plants, and putatively contribute to reducing nanotoxicity in plants. Here, we studied the interactions between ZnO NPs and maize plants inoculated with or without AMF in ZnO NPs-spiked soil. ZnO NPs had no significant adverse effects at 400 mg/kg, but inhibited both maize growth and AM colonization at concentrations at and above 800 mg/kg. Sufficient addition of ZnO NPs decreased plant mineral nutrient acquisition, photosynthetic pigment concentrations, and root activity. Furthermore, ZnO NPs caused Zn concentrations in plants to increase in a dose-dependent pattern. As the ZnO NPs dose increased, we also found a positive correlation with soil diethylenetriaminepentaacetic acid (DTPA)-extractable Zn. However, AM inoculation significantly alleviated the negative effects induced by ZnO NPs: inoculated-plants experienced increased growth, nutrient uptake, photosynthetic pigment content, and SOD activity in leaves. Mycorrhizal plants also exhibited decreased ROS accumulation, Zn concentrations and bioconcentration factor (BCF), and lower soil DTPA-extractable Zn concentrations at high ZnO NPs doses. Our results demonstrate that, at high contamination levels, ZnO NPs cause toxicity to AM symbiosis, but AMF help alleviate ZnO NPs-induced phytotoxicity by decreasing Zn bioavailability and accumulation, Zn partitioning to shoots, and ROS production, and by increasing mineral nutrients and antioxidant capacity. AMF may play beneficial roles in alleviating the negative effects and environmental risks posed by ZnO NPs in agroecosystems.
authors.affiliation: Agricultural College, Henan University of Science and Technology, Luoyang 471003, People's Republic of China. Electronic address: wfy1975@163.com.
authors.forename: Fayuan
authors.initials: F
authors.lastname: Wang
authors.affiliation: Agricultural College, Henan University of Science and Technology, Luoyang 471003, People's Republic of China; College of Resources and Environment, Southwest University, Chongqing 400716, People's Republic of China; Life Science Department, Luoyang Normal University, Luoyang 471022, Henan, People's Republic of China.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Agricultural College, Henan University of Science and Technology, Luoyang 471003, People's Republic of China.
authors.forename: Zhaoyong
authors.initials: Z
authors.lastname: Shi
authors.affiliation: Life Science Department, Luoyang Normal University, Luoyang 471022, Henan, People's Republic of China.
authors.forename: Ruijian
authors.initials: R
authors.lastname: Tong
authors.affiliation: Plant and Microbial Biology Department, University of California Berkeley, CA, USA.
authors.forename: Catharine A
authors.initials: CA
authors.lastname: Adams
authors.affiliation: College of Resources and Environment, Southwest University, Chongqing 400716, People's Republic of China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Shi
mesh_terms: D055137:Glomeromycota / Q000502:physiology*; D053768:Metal Nanoparticles / Q000633:toxicity*; D038821:Mycorrhizae / Q000502:physiology*; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000493:pharmacokinetics / Q000633:toxicity*; D013482:Superoxide Dismutase / Q000378:metabolism; D013559:Symbiosis; D003313:Zea mays / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology; D015032:Zinc / Q000493:pharmacokinetics / Q000633:toxicity*; D015034:Zinc Oxide / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D017382:Reactive Oxygen Species; D012989:Soil Pollutants; D013482:Superoxide Dismutase; D015032:Zinc; D015034:Zinc Oxide
keywords: Arbuscular mycorrhizal fungi; Maize; Phytotoxicity; ZnO nanoparticles