Delivery of Abscisic Acid to Plants Using Glutathione Responsive Mesoporous Silica Nanoparticles

Abstract

An intracellular glutathione (GSH) responsive phytochemical delivery system based on thiol gated mesoporous silica nanoparticles (MSNs) was developed and tested on the model plant Arabidopsis thaliana. In the present study, monodispersed MSNs with particle diameters of ~20 nm and pore sizes of ~2.87 nm were synthesized and modified. Abscisic acid (ABA), a key phytohormone, was entrapped in the mesopores of MSNs and then the pore entrances of MSNs were covered with decanethiol gatekeepers through GSH-cleavable disulfide linkages. An in vitro release test of ABA from decanethiol gated MSNs proved that there was efficient loading and entrapment of phytochemicals in the absence of a GSH redox trigger. Most importantly, in planta experiments demonstrated that GSH-mediated release of ABA from the pores of MSNs significantly reduced the leaf stomatal aperture and inhibited water loss of treated plants. Moreover, compared with the usage of free ABA, the controlled release of the encapsulated phytohormone from MSNs markedly prolonged the expression of the ABA inducible marker gene (AtGALK2) and finally, improved the drought resistance ability of Arabidopsis seedlings under drought stress. Therefore, the concept of using short-chain molecules as gatekeepers to encapsulate biomolecules in MSNs was demonstrated. The application of MSNs with redox-responsive gatekeepers has been shown in this study to be a potential and efficient technique to deliver phytochemicals into plants and release them in a controllable fashion.

Development of stimuli-responsive nano-based pesticides: emerging opportunities for agriculture

“…Several redox-responsive systems have been developed, employing gatekeepers including organic components, inorganic crystals, polymers, and biomolecules [48]. Some examples of gatekeepers are cyclodextrins [49], curcumin [50], ZnO quantum dots [51], PEG [52], and hyaluronic acid [53].…”

“…Stimuli-responsive nanoparticles can be applied to soils in order to provide targeted and slow release of fertilizers, fungicides, herbicides, and plant growth regulators. Sun et al [48] developed a redox-responsive system for encapsulation of abscisic acid, a plant growth regulator responsible for regulating physiological changes in plants and increasing glutathione levels under stress conditions. Trials using Arabidopsis plants under hydric stress conditions showed that treatment with the nanoparticles induced physiological changes, with closure of the stomata in order to avoid water loss, as well as high expression of the AtGALK2 gene related to stress relief.…”

Addressing Nanomaterial Immunosafety by Evaluating Innate Immunity across Living Species

“…In particular, mesoporous silica NP, already used as anticancer drug delivery systems, are expected to be a promising carrier of resistance inducers. [224] To date engineered NP have been successfully used as phytohormone delivery systems [225] or like pesticide carriers in order to target their activity and reduce the indiscriminate leaking of toxic compounds, alleviating the potential adverse effects on the environment. [226] Functionalized mesoporous silica NP with a redox-responsive gatekeeper system, able to specifically release the resistance inducer and avoiding premature leakage in the delivery process, demonstrated their potential application in agriculture.…”

Naturally Occurring and Synthetic Mesoporous Nanosilica: Multimodal Applications in Frontier Areas of Science

“…133,[150][151][152] Recently, an intracellular glutathione (GSH) responsive abscisic acid (ABA) delivery system has been developed based on thiol gated MSNs. 153 Monodispersed MSNs with particle diameter of $ 20 nm and pore size of $ 2:87 nm were synthesized and modi¯ed using decanthiol as gatekeepers. It was found that GSH mediated the release of entrapped ABA and hence reduced the leaf stomatal aperture and water loss.…”