Nonsense-mediated decay as RNA quality control mechanism: An opportunity for developing viral interference in plants

Nonsense-mediated decay (NMD) is a crucial RNA surveillance mechanism that not only prevents synthesis of harmful truncated proteins but also keeps an eye on the quality and quantity check of mRNA in an efficient manner for effective gene expression. Viruses are in a continuous arm race with their host organisms to establish infection. Hence, hosts also constantly evolve new means of defence to exploit and suppress infection by the virus. In maximizing coding capacity in a small genome, several families of plant RNA viruses were documented to have NMD substrate features as a by-product. Although these features aid in viral infection, they are also susceptible to the host NMD pathway. In response, some viruses have evolved to bypass or disrupt the host NMD mechanism via cis-acting or trans-acting viral factors. By targeting the NMD pathway, it is possible to reduce the stability of pathogenic RNAs, leading to decreased pathogen viability and resistance. This review explores the mechanisms of NMD, its role in RNA quality control and the potential applications of manipulating NMD to combat pathogen resistance in agricultural and natural ecosystems. This review discusses the viral system circumventing the host NMD for their successful replication in plants. Moreover, an increased number of studies on the evasion mechanism of RNA viruses from host NMD provide insight into the molecular means of the NMD mechanism and may be linked to device defence strategies in agro-economic plants, which is an interesting future research possibility.