CRISPR/Cas9-Mediated genetically edited ornamental and aromatic plants: A promising technology in phytoremediation of heavy metals

Abstract

Phytoremediation, as a green, sustainable, and cost-effective plant-based remediation technology has garnered great attention for remediating heavy metals (HMs) from polluted soil and water resources. However, HM type and concentration, phytoremediation method, climatic conditions, type of plant species, potential of biomass production, level of plant sensitivity, and signaling pathways efficiency are all crucial factors affecting plant's phytoremediation performance. Ornamental, medicinal, and aromatic plants with medicinal, pharmaceutical, cosmetics, and decorative uses are promising species for the phytoremediation of HMs from soil and water due to their fast growth and high biomass production. Furthermore, new genetic technologies such as, the clustered regularly interspaced short palindromic repeats – CRISPR associated protein 9 (CRISPR/Cas9) gene/genome editing system, may become a tool that provides sustainable phytoremediation by targeted editing of genes of interest to improve the phytoremediation capacity of the selected ornamental plants (OPs) without raising genetically modified organisms (GMO) concerns. This review summarizes the current state of knowledge associated with protection mechanisms and molecular aspects of plant tolerance to HMs by ornamental, medicinal and aromatic plants. The review also focuses on the use of genetically engineered ornamental and medicinal aromatic plants applying recent advances in CRISPR/Cas9 genome editing to enhance phytoremediation properties. Risk assessments and regulatory approaches associated with environmental protection, livestock, and human health for transgenic plants released into the environment are also discussed. This work elicits interdisciplinary aspects and an understanding of the long-term management of HMs using ornamental, medicinal, and aromatic plants in an innovative way that no prior study has considered.