Since the 1990s, the virus-induced gene silencing (VIGS) method has been successfully developed for many plants, including several agriculturally important species. The method is often used in studies examining interactions between genes in plants, because it is simple, fast, and affordable. In this method, a gene that we want to silence is introduced into the plant by a recombinant viral vector. This triggers the post-transcriptioal gene silencing (PTGS) mechanism, which degrades the host mRNA through RNAi, dicer and the RISC complex. This prevents the formation of protein, which is manifested on the plant as the appearance of a silenced phenotype. More than 30 different viral vectors are known, and some of the most commonly used are tobacco mosaic virus (TMV), potato virus X (PVX), apple latent spherical virus (ALSV), barley stripe mosaic virus (BSMV) and tobacco rattle virus (TRV). The easiest way to introduce a viral vector into a host plant is by using the vector transporter bacterium A. tumefaciens, which is able to transfer its T-DNA from the Ti-plasmid into the plant genome. VIGS is also promising in the future, as the discovery of new viral vectors and the optimization of infiltration methods of host plants will make it possible to silence genes in plants for which this is not yet possible. This will allow us to better understand the function of genes in plants and the interactions between them.
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