When agriculture talks about crop research being done in a lab, many people’s minds immediately go to items such as corn and soybeans. But biotech advances reach well beyond those commodities. One example has been showcased in recent months in Spain, where researchers have used tools that regulate gene expression in order to produce tomato plants that are resistant to the spotted wilt virus (TSWV). Their work, which was published in The Plant Journal, helps to prove the usefulness of these types of strategies to generate crops that are resistant to viral infections.
The gene silencing mediated by RNA or RNAi is a crucial technique for modern biology, as it allows for the selective “turning on or off” of genes; and in plants, it has been successfully used to induce resistance to some viruses. The efforts being done in Spain were a collaboration of the Plant Molecular and Cellular Biology Institute at Valencia’s Polytechnic University, and the Spanish National Research Council.
Institute researcher Alberto Carbonell explains that “one of the most successful RNAi-based antiviral techniques consists of inducing the expression of small artificial RNAs designed to inhibit the replication of the most viral RNAs in the plants. In this study, we have worked with two types of small artificial RNAs, artificial microRNAs or amiRNAs, and synthetic trans-acting small interfering RNAs, or syn-tasiRNAs. Then we compared the level of resistance to a virus of great economic importance, TSWV, of plants that express a single antiviral amiRNA and of plants that simultaneously express four antiviral syn-tasiRNAs, each with a different target location.”
The work of the institute’s researchers has shown that plants that express a single antiviral amiRNA are more susceptible to TSWV, due to the fact that the virus easily accumulates mutations in the amiRNA’s target location, which allows it to evade its action and continue with the infection. On the other hand, a majority of plants that simultaneously express four antiviral syn-tasiRNAs are totally resistant to TSWV, probably due to the combined effect of each syn-tasiRNA.
“We believe that the probability of the virus accumulating mutations simultaneously in the four target locations is very small. With our work, we have been able to produce tomato plants that are resistant to TSWV, as well as proving the use and suitability of the strategy based on syn-tasiRNAs to generate crops that are resistant to viral infections,” Carbonell said.