title: Molecular and physiological responses to titanium dioxide and cerium oxide nanoparticles in Arabidopsis.
abstract: Changes in tissue transcriptomes and productivity of Arabidopsis thaliana were investigated during exposure of plants to 2 widely used engineered metal oxide nanoparticles, titanium dioxide (nano-titania) and cerium dioxide (nano-ceria). Microarray analyses confirmed that exposure to either nanoparticle altered the transcriptomes of rosette leaves and roots, with comparatively larger numbers of differentially expressed genes found under nano-titania exposure. Nano-titania induced more differentially expressed genes in rosette leaves, whereas roots had more differentially expressed genes under nano-ceria exposure. MapMan analyses indicated that although nano-titania up-regulated overall metabolism in both tissues, metabolic processes under nano-ceria remained mostly unchanged. Gene enrichment analysis indicated that both nanoparticles mainly enriched ontology groups such as responses to stress (abiotic and biotic), and defense responses (pathogens), and responses to endogenous stimuli (hormones). Nano-titania specifically induced genes associated with photosynthesis, whereas nano-ceria induced expression of genes related to activating transcription factors, most notably those belonging to the ethylene responsive element binding protein family. Interestingly, there were also increased numbers of rosette leaves and plant biomass under nano-ceria exposure, but not under nano-titania. Other transcriptomic responses did not clearly relate to responses observed at the organism level, possibly because of functional and genomic redundancy in Arabidopsis, which may mask expression of morphological changes, despite discernable responses at the transcriptome level. In addition, transcriptomic changes often relate to transgenerational phenotypic development, and hence it may be productive to direct further experimental work to integrate high-throughput genomic results with longer term changes in subsequent generations. Environ Toxicol Chem 2017;36:71-82. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
authors.affiliation: National Research Council, Western Ecology Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Corvallis, Oregon, USA.
authors.forename: Laxminath
authors.initials: L
authors.lastname: Tumburu
authors.affiliation: Western Ecology Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Corvallis, Oregon, USA.
authors.forename: Christian P
authors.initials: CP
authors.lastname: Andersen
authors.affiliation: Western Ecology Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Corvallis, Oregon, USA.
authors.forename: Paul T
authors.initials: PT
authors.lastname: Rygiewicz
authors.affiliation: Western Ecology Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Corvallis, Oregon, USA.
authors.forename: Jay R
authors.initials: JR
authors.lastname: Reichman
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D002563:Cerium / Q000737:chemistry / Q000633:toxicity*; D020869:Gene Expression Profiling; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D010788:Photosynthesis / Q000187:drug effects / Q000235:genetics; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics; D014025:Titanium / Q000737:chemistry / Q000633:toxicity*; D059467:Transcriptome / Q000187:drug effects*
chemical_list: C009495:titanium dioxide; D002563:Cerium; C030583:ceric oxide; D014025:Titanium
keywords: Arabidopsis thaliana; Engineered nanoparticles; Growth; Nano-ceria; Nano-titania; Transcriptome