Pectinase-responsive carriers based on mesoporous silica nanoparticles for improving the translocation and fungicidal activity of prochloraz in rice plants

Stimuli-responsive carriers as delivery systems of agrochemicals into plants can increase the utilization efficiency of pesticides against target pests and reduce hazards on nontarget living organisms and the environment. In the present work, prochloraz was loaded into mesoporous silica nanoparticles (MSNs) and coated by pectin on the particle surface as a gatekeeper to study the translocation and distribution of prochloraz@MSN-pectin (Pro@MSN-Pec) in rice plants. The results showed that Pro@MSN-Pec was successfully fabricated and had an average size of 70.89 nm and a good loading efficiency (30% w/w). The MSNs were labeled using fluorescein isothiocyanate (FITC) to track the distribution of the carriers in the rice plants. Confocal scanning analysis showed that MSN-FITC could be transported to all rice parts from the treated leaves or roots. The release of prochloraz (Pro) from Pro@MSN-Pec was pectinase-dependent. Compared with the commercial emulsifiable concentrate (EC formulation) of Pro, the Pro@MSN-Pec formula had a better uptake and translocation in rice plants as well as a longer duration and better antifungal activity against rice blast disease ( Magnaporthe oryzae ). The final residue level of Pro in the rice plants was lower than the maximum residue limits. These results suggest that the use of stimuli-responsive carriers as pesticide-delivery systems in plants can be potentially implemented in applied agriculture.