Rational design of ROS scavenging and fluorescent gold nanoparticles to deliver siRNA to improve plant resistance to Pseudomonas syringae

Abstract Bacterial diseases are one of the common issues to result in crop loss world-widely, and the increasing usage of chemical pesticides has caused the occurrence of resistance in pathogenic bacteria and environmental pollution problems. Nanomaterials mediated gene silencing is started to display powerful efficiency and environmental friendliness for improving plant disease resistance. However, the internalization of nanomaterials and the physiological mechanism behind nano-improved plant disease resistance are still rarely understood. Herein, we engineered the polyethyleneimine (PEI) functionalized gold nanoparticles (PEI-AuNPs) with fluorescent property and ROS scavenging activity to act as siRNA delivery platform. Besides the loading, protection and delivering of nucleic acid molecules in plant mature leaf cells by PEI-AuNPs, its fluorescent property further enables the traceability of the distribution of the loaded nucleic acid molecules in cells. In addition, PEI-AuNPs delivery system successfully mediated defense regulated gene silencing, thus improving plant disease resistance by reducing bacterial number, balancing ROS content, enhancing antioxidant enzyme activity, and improving chlorophyll fluorescence performance. Our results showed the benefits of AuNP-based RNAi technology in improving plant disease resistance and the potential of plant nanobiotechnology to protect agricultural production.