RNA silencing: the future potential strategy for engineering virus resistance in plants

Plant viruses adversely affect worldwide agriculture and cause immense crop yield losses globally. Scientists have developed various strategies to combat the viral attacks on plants and one such ground-breaking discovery is the RNA interference (RNAi), also known as RNA silencing. RNA silencing has evolved as a major tool for developing viral resistance in plants through gene silencing that involves the intricate use of various small RNAs, such as small interfering RNAs (siRNAs), endogenous microRNAs (miRNAs), artificial miRNAs (amiRNAs), hairpin RNAs (hpRNAs), double-stranded (ds) RNA sprays (topical applications), and the less prevalent short hairpin (sh) RNAs. With tailor-made constructs, RNAi has opened the avenues for the immense potential to down-regulate the desired viral target genes, leading to reduced viral pathogenicity in several crop plants leading to enhanced sustainability in agriculture and food security for the teeming millions across the globe. In this article, we have reviewed the advances made in the generation of virus-resistant plants by using RNAi-based approaches, particularly siRNA- and amiRNA-mediated technologies. Despite certain issues with delivery, specificity, resistance, and safety that impede the RNAi-based treatments, targeted RNA silencing is expected to revolutionize the future agricultural research with tailor-made stress-tolerant crop plants.