RNA interference (RNAi) is a regulatory mechanism of gene expression mediated by small RNAs. By using the RNAi technique, exogenous double-stranded RNA (dsRNA) designed to target mRNA, suppresses target gene expression levels in plants. In this study, we adopted the RNAi mechanism as a tool to protect plants from viruses. We designed and synthesized several dsRNAs targeting the pepper mottle virus (PepMoV) genes HC-Pro and NIb. When used on Nicotiana benthamiana plants, these dsRNAs protected the plant against viral infection over a specific period. By optimizing dsRNA and virus injection time, the protection efficiency of dsRNA by targeting virus genes could be maximized. It seems that exogenous dsRNA-derived RNA-induced silencing complex was able to defend the host against viral infection instantly. Furthermore, each dsRNA designed to target different regions within a transcript had varying levels of effects on virus survival in the host plants. When targeting the middle part of both the NIb and HC-Pro genes using the dsRNAs, the highest viral growth inhibitory effect was observed. An RLM-5′ RACE was performed using plant leaves infected with PepMoV after dsRNA treatment and it was observed that most of the mRNA cleavages occurred close to the 3′ part within the dsRNA target position on the mRNA. These results suggest that the dsRNA tool can be used as a plant vaccine platform for crop protection.

中文翻译：

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双链RNA赋予本氏烟草对胡椒斑驳病毒的抗性

RNA干扰（RNAi）是小RNA介导的基因表达的调控机制。通过使用RNAi技术，旨在靶向mRNA的外源双链RNA（dsRNA）可以抑制植物中的靶基因表达水平。在这项研究中，我们采用了RNAi机制作为保护植物免受病毒侵害的工具。我们设计和合成了几种针对胡椒斑驳病毒（PepMoV）基因HC-Pro和NIb的dsRNA。当在本氏烟草植物上使用时，这些dsRNA可在特定时期内保护植物免受病毒感染。通过优化dsRNA和病毒注射时间，可以最大化针对病毒基因的dsRNA的保护效率。看来外源性dsRNA衍生的RNA诱导的沉默复合物能够立即防御病毒感染宿主。此外，设计用于靶向转录本中不同区域的每个dsRNA对宿主植物中病毒存活的影响程度不同。当使用dsRNA靶向NIb和HC-Pro基因的中间部分时，观察到最高的病毒生长抑制作用。在dsRNA处理后，使用感染了PepMoV的植物叶片进行了RLM-5'RACE，并且观察到大多数mRNA切割均发生在mRNA上dsRNA目标位置的3'部分附近。这些结果表明，dsRNA工具可以用作植物保护作物的疫苗平台。在dsRNA处理后，使用感染了PepMoV的植物叶片进行了RLM-5'RACE，观察到大多数mRNA切割均发生在mRNA上dsRNA目标位置的3'部分附近。这些结果表明，dsRNA工具可以用作植物保护作物的疫苗平台。在dsRNA处理后，使用感染了PepMoV的植物叶片进行了RLM-5'RACE，并且观察到大多数mRNA切割均发生在mRNA上dsRNA目标位置的3'部分附近。这些结果表明，dsRNA工具可以用作植物保护作物的疫苗平台。