RNA silencing in plants: applications in crop production

Genetic modification of crop plants requires a stable transformation and efficient expression of the transferred gene in host tissues. This is many times compromised by lack of suitable transformation method, the time needed for generation of transgenics and also the silencing of the transferred gene especially if it is homologous to the native gene(s). RNA silencing is a collective term for sequence of events that leads to targeted RNA-degradation and silencing or knocking-down of gene expression. It was first discovered in plants, and later similar mechanisms were identified in fungi, worms, insects and mammals. RNA silencing appears to be an endogenous mechanism against viral pathogens and transposons. Thus, many plant viruses have also evolved to encode suppressors of RNA silencing. RNA silencing is induced by various means such as particle bombardment of individual cells, agroinfiltration by agrobacteria and using viral vectors, and they serve as tools to silence target genes to allow not only orphan gene analysis but also the regulation of metabolic pathways. Suppressor proteins can facilitate plant transformation process and also delay the induction of RNA silencing process, thus, allowing more time for a heterologous protein to be expressed. In the future, the increase of the use of the RNA silencing mechanisms in crop production is likely to be seen.