Department of Entomology, College of Plant Protection, Nanjing Agricultural University/The Key Laboratory of Monitoring and Management of Plant Diseases and Insects (Ministry of Agriculture), The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing 210095, China; College of Food Science and Engineering, Nanjing University of Finance and Economics, The Jiangsu Province Center of Cooperative Innovation for Modern Grain Circulation and Security, Nanjing 210023, China.
Department of Entomology, College of Plant Protection, Nanjing Agricultural University/The Key Laboratory of Monitoring and Management of Plant Diseases and Insects (Ministry of Agriculture), The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing 210095, China.
Pestic Biochem Physiol. 2020 May;165:104467. doi: 10.1016/j.pestbp.2019.10.005. Epub 2019 Oct 22.
RNA interference (RNAi) has proven to be a very promising prospect for insect pest control. However, low RNAi efficacy limits further development of this biotechnology for use on lepidopteran insects, including the rice striped stem borer (SSB) (Chilo suppressalis), one of the major destructive rice pests. In this work, the application of various nanoparticles (NPs) by which double-stranded RNA (dsRNA) could be encapsulated was evaluated as an alternative delivery strategy to potentially increase the bioactivity of dsRNA. Three NPs, chitosan, carbon quantum dot (CQD), and lipofectamine2000, complexed with dsRNA (to target the glyceraldehyde-3-phosphate dehydrogenase gene (G3PDH)) were tested to examine their use in controlling SSB. Relative mRNA expressions were quantified using qPCR to evaluate knockdown efficiency of NP-dsRNA treated larvae, and the correlated dsRNA-mediated SSB larval mortality was tested. Thereafter, the content dynamics of hemolymph dsRNA after ingesting different NP-dsRNA were monitored in vivo; the hemolymph dsRNA content was in ratios of 5.67, 9.43, and 1 with chitosan, CQD, and lipofectamine2000 induced samples, respectively. The results demonstrated that all three tested NPs led to efficient feeding delivery by improving both dsRNA stability and cellular uptake equally. Furthermore, there was a strong correlation (r= 0.9854) between the hemolymph dsRNA contents and the average RNAi depletions in the non-gut tissues of SSB. Overall, our results strongly suggest that due to its strong endosomal escaping ability, CQD was the most efficient carrier for inducing systemic RNAi, and thereby causing effective gene silencing and mortality in SSB.
RNA 干扰（RNAi）已被证明是一种很有前途的昆虫防治方法。然而，低 RNAi 功效限制了这项生物技术在鳞翅目昆虫（包括水稻二化螟（Chilo suppressalis），这是一种主要的破坏性水稻害虫之一）上的进一步发展。在这项工作中，评估了各种纳米颗粒（NPs）作为一种替代传递策略的应用，这些 NPs 可以包裹双链 RNA（dsRNA），以提高 dsRNA 的生物活性。测试了三种 NPs（壳聚糖、碳量子点（CQD）和脂质体 2000）与 dsRNA（靶向甘油醛-3-磷酸脱氢酶基因（G3PDH））复合，以研究它们在控制二化螟中的应用。使用 qPCR 定量相对 mRNA 表达，以评估 NP-dsRNA 处理幼虫的敲低效率，并测试相关的 dsRNA 介导的二化螟幼虫死亡率。此后，在体内监测摄入不同 NP-dsRNA 后血液 dsRNA 的含量动态；血液 dsRNA 含量分别为壳聚糖、CQD 和脂质体 2000 诱导样品的 5.67、9.43 和 1 倍。结果表明，所有三种测试的 NPs 通过同样提高 dsRNA 稳定性和细胞摄取效率，都能有效地进行喂养传递。此外，血液 dsRNA 含量与二化螟非肠道组织中的平均 RNAi 耗竭之间存在很强的相关性（r=0.9854）。总的来说，我们的结果强烈表明，由于 CQD 具有很强的内体逃逸能力，它是诱导系统性 RNAi 的最有效载体，从而在二化螟中引起有效的基因沉默和死亡率。
