Clay nanoparticles efficiently deliver small interfering RNA to intact plant leaf cells

Layered double hydroxide nanoparticles rapidly penetrate intact plant leaf cells and chloroplasts and efficiently deliver small interfering RNA to downregulate targeted genes.J. Y., B.C. R.Z., and Z.P.X. conceptualized and designed the research. J.Y. conducted experiments, data analysis, and wrote the first draft. M.W conducted experiments, data analysis, and conceptual visualization. S.B. and C.M. conducted the experiments. J.Y., R.Z., B.C., N.M., and Z.P.X. wrote and revised the manuscript. All authors read and commented on the manuscript. RNA interference is triggered in plants by the exogenous application of double-stranded RNA or small interfering RNA (siRNA) to silence the expression of target genes. This approach can potentially provide insights into metabolic pathways and gene function and afford plant protection against viruses and other plant pathogens. However, the effective delivery of biomolecules such as siRNA into plant cells is difficult because of the unique barrier imposed by the plant cell wall. Here, we demonstrate that 40-nm layered double hydroxide (LDH) nanoparticles are rapidly taken up by intact Nicotiana benthamiana leaf cells and by chloroplasts, following their application via infiltration. We also describe the distribution of infiltrated LDH nanoparticles in leaves and demonstrate their translocation through the apoplast and vasculature system. Furthermore, we show that 40-nm LDH nanoparticles can greatly enhance the internalization of nucleic acids by N. benthamiana leaf cells to facilitate siRNA-mediated downregulation of targeted transgene mRNA by >70% within 1 day of exogenous application. Together, our results show that 40-nm LDH nanoparticle is an effective platform for delivery of siRNA into intact plant leaf cells.

Automated summary

This study demonstrates that layered double hydroxide nanoparticles can quickly penetrate plant leaf cells and chloroplasts, delivering small interfering RNA to downregulate targeted genes. This has significant implications for plant protection against viruses and understanding gene function.