A nanomaterial for the delivery of dsRNA as a strategy to alleviate viral infections in maize

The current methods for pest managements in cereal crops rely mainly on the applications of conventional chemicals, which are known to have low pest control efficiencies and are less environmentally friendly. The primary aim of this research endeavor was to devise a specific, efficient and eco-friendly biological agent capable of mitigating maize lethal necrosis (MLN), a viral disease that affected maize productivity, and mainly caused by coinfection of maize chlorotic mottle virus (MCMV) and sugarcane mosaic virus (SCMV). Through this study, we have found that silencing Ferredoxin 3 (ZmFd3) expression in maize can significantly reduce the damages caused by MCMV and/or SCMV infections. Based on this finding, we have developed a LNPs-mediated nanotechnology to suppress MCMV and/or SCMV infections. Using this nanotechnology, we have confirmed that the cationic/anionic liposomes (CLPs and ALPs) can be used to package and promote ZmFd3-dsRNA spread in maize plants. Through leaf spray, we have determined that the anti-MCMV and anti-SCMV activities of ZmFd3@CLPs and ZmFd3@ALPs nanoparticles can reach 52.46 ∼ 79.83 % at 6 days post virus inoculation (dpi). Because ZmFd3 is involved in hypersensitive response (HR), and can interact with MCMV p7b and SCMV HC-Pro, we designed an FHP-dsRNA to target ZmFd3, MCMV p7b, and SCMV HC-Pro transcripts for silencing in plants simultaneously. The result showed that both FHP@CLPs and FHP@ALPs nanoparticles can provide excellent, although short, protection to maize and sorghum plants to MCMV and SCMV infections. Overall, this study has developed a novel nanotechnology that can be used to mitigate virus infection in cereal crops through, RNA interference (RNAi).