Plant Response to Metal-Containing Engineered Nanomaterials: An Omics-Based Perspective

The
increasing use of engineered nanomaterials (ENMs) raises questions
regarding their environmental impact. Improving the level of understanding
of the genetic and molecular basis of the response to ENM exposure
in biota is necessary to accurately assess the true risk to sensitive
receptors. The aim of this Review is to compare the plant response
to several metal-based ENMs widely used, such as quantum dots, metal
oxides, and silver nanoparticles (NPs), integrating available “omics”
data (transcriptomics, miRNAs, and proteomics). Although there is
evidence that ENMs can release their metal components into the environment,
the mechanistic basis of both ENM toxicity and tolerance is often
distinct from that of metal ions and bulk materials. We show that
the mechanisms of plant defense against ENM stress include the modification
of root architecture, involvement of specific phytohormone signaling
pathways, and activation of antioxidant mechanisms. A critical meta-analysis
allowed us to identify relevant genes, miRNAs, and proteins involved
in the response to ENMs and will further allow a mechanistic understanding
of plant–ENM interactions.