Impact of Nanomaterials on Plant Secondary Metabolism

 Plants encounter various nanomaterials (NMs) as pesticides and fertil-izers. It is also possible that nanomaterials reach plants as waste from consumer prod-ucts and industry. The effects of such NMs on plants have been widely studied, and both positive and negative effects of NMs on plant growth and development have been reported. Recent metabolomics studies suggest that nanoparticles affect the concen-tration of secondary metabolites in plants by modulating reactive nitrogen/oxygen species, gene expression, and signaling pathways. Secondary metabolites are plant compounds that accumulate in plants through their secondary metabolism. To date, more than 200,000 defined structures of secondary metabolites have been identi-fied, among which many of them possess antibacterial, antifungal, antiviral, anti-inflammatory, hepatoprotective, antidepressant, antioxidant, neuroprotective, and anticancer properties. The application of elicitors is a simple strategy to increase the production of secondary metabolites in plant cell and tissues. The ability of nano-materials to induce plant secondary metabolism has recently been exploited in the elicitation of pharmaceutically important compounds from various plant species. The ability of different NMs to induce the accumulation of different classes of compounds in the same plant species has also been accomplished. The molecular mechanisms behind the effects of NMs on plant secondary metabolism revealed the putative genes involved in NM-mediated elicitation of various plant compounds in several reports. This chapter reviews the current understanding of the effects of nanoparticles on plant secondary metabolism and the elicitation of pharmacologically important compounds from plant species.