Designer nanoparticles for plant cell culture systems: Mechanisms of elicitation and harnessing of specialized metabolites.

Plant cell culture systems have become an attractive and sustainable approach to produce high-value and commercially significant metabolites under controlled conditions. Strategies involving elicitor supplementation into plant cell culture media are employed to mimic natural conditions for increasing the metabolite yield. Studies on nanoparticles (NPs) that have investigated elicitation of specialized metabolism have shown the potential of NPs to be a substitute for biotic elicitors such as phytohormones and microbial extracts. Customizable physicochemical characteristics allow the design of monodispersed-, stimulus-responsive-, and hormone-carrying-NPs of precise geometries to enhance their elicitation capabilities based on target metabolite/plant cell culture type. We contextualize advances in NP-mediated elicitation, especially stimulation of specialized metabolic pathways, the underlying mechanisms, impacts on gene regulation, and NP-associated cytotoxicity. The novelty of the concept lies in unleashing the potential of designer NPs to enhance yield, harness metabolites, and transform nanoelicitation from exploratory investigations to a commercially viable strategy.