Abstract
Topical application of double-stranded RNA (dsRNA) can induce RNA interference (RNAi) and modify traits in plants without genetic modification. However, delivering dsRNA into plant cells remains challenging. Using developing tomato (Solanum lycopersicum) pollen as a model plant cell system, we demonstrate that layered double hydroxide (LDH) nanoparticles up to 50 nm in diameter are readily internalized, particularly by early bicellular pollen, in both energy-dependent and energy-independent manners and without physical or chemical aids. More importantly, these LDH nanoparticles efficiently deliver dsRNA into tomato pollen within 2-4 h of incubation, resulting in an 89% decrease in transgene reporter mRNA levels in early bicellular pollen 3-d post-treatment, compared with a 37% decrease induced by the same dose of naked dsRNA. The target gene silencing is dependent on the LDH particle size, the dsRNA dose, the LDH-dsRNA complexing ratio, and the treatment time. Our findings indicate that LDH nanoparticles are an effective nonviral vector for the effective delivery of dsRNA and other biomolecules into plant cells.