ToBRFV and Breaking Resistance in Peppers
This blog continues our coverage of the Tomato brown rugose fruit virus (ToBRFV), but this time, we are giving an update on peppers (mostly bell peppers but also others in the Capsicum genus) and its ability to overcome plant resistance. While this virus primarily targets tomatoes, it’s also a significant concern for pepper cultivation.
What is ToBRFV and Genetic Resistance?
ToBRFV is a highly infectious and rapidly spreading RNA virus that belongs to the Tobamovirus genus. First discovered in 2015 in Jordan, it has since spread to at least 35 countries across four continents, posing a severe threat to solanaceous crops like tomatoes and peppers. Genetic resistance is like having a built-in defense system in plants. Some plants have genes that help them fight off diseases, much like how our immune system helps us fight off colds. Therefore, when a plant has these special genes, it’s less likely to get sick from certain viruses.
Resistance Breaking Ability by ToBRFV
Sometimes, even plants with strong genetic resistance can be affected by viruses like ToBRFV. This happens because the virus can change or evolve in a way that allows it to bypass the plant’s natural defenses. Think of it like this: if the plant’s resistance is a locked door, Tobrfv can sometimes find a new key that opens it. When this happens, the virus overcomes the plant’s genetic resistance and can cause disease.
One of the most concerning aspects of ToBRFV is its ability to overcome genetic resistance mechanisms in both tomatoes and peppers. It can infect tomato plants harboring the commonly deployed Tm-1, Tm-2, and Tm-2² resistance genes and pepper plants carrying the L¹ and L² alleles under certain conditions.
Hypersensitive response: a rapid localized cell death that occurs at the point of pathogen penetration and is associated with disease resistance. Experts think plants do this to stop the pathogen from spreading outwards to healthy areas.
Key Papers to Read:
- EPPO Datasheet: Tomato brown rugose fruit virus. Access pdf here: https://www.semanticscholar.org/paper/EPPO-Datasheet%3A-Tomato-brown-rugose-fruit-virus/b2b48fc3358cc2437be8c80d8395b8804b22b561
- Tomato genetic resistance to tobamoviruses is compromised. https://www.actahort.org/books/1316/1316_13.htm
- Screening of wild tomato species and interspecific hybrids for resistance/tolerance to Tomato brown rugose fruit virus (ToBRFV). https://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392022000100189&lng=en&nrm=iso&tlng=en
- Tomato brown rugose fruit virus (ToBRFV): Current status and future. Found here https://dergipark.org.tr/tr/pub/mediterranean/issue/53501/705740 (Turkish paper)
- Pepper Plants Harboring L Resistance Alleles Showed Tolerance toward Manifestations of Tomato Brown Rugose Fruit Virus Disease. https://www.mdpi.com/2223-7747/11/18/2378