A Promising Genetic Line in the Fight Against ToBRFV

The Tomato Brown Rugose Fruit Virus (ToBRFV) remains a significant concern for the global tomato processing industry. In a crucial development, researchers from the USDA’s Agricultural Research Service (ARS) and their university partners have identified an existing tomato line, developed three decades ago, that exhibits good resistance to this damaging virus.  

Understanding ToBRFV and Management

As the industry is well aware, ToBRFV impacts tomato crops, causing fruit discoloration and leaf distortion that leads to yield losses. Its easy spread through contaminated materials and its ability to overcome current commercial resistance genes make it particularly challenging. Current management primarily relies on strict hygiene protocols, including cleaning and sanitizing growing environments.  

Genetic Resistance: The Long-Term Strategy

While hygiene is essential, the focus for sustainable control is genetic resistance. “To minimize the impact of ToBRFV, it is crucial to identify new sources of genetic resistance that can be used to breed virus-resistant tomato cultivars,” explains Kai Ling, an ARS research plant pathologist. He emphasizes that “deploying cultivars with resistance genes is the critical strategy to combat tobamoviruses.”  

A study published in the Plant Biotechnology Journal details a specific tomato line, tomatoNN. Created in the 1990s by ARS plant molecular geneticist Barbara Baker and her team, this line incorporates the ‘N’ gene from a wild tobacco plant, originally providing resistance to the tobacco mosaic virus (TMV).  

Temperature’s Influence on Resistance

Ling and his team discovered that tomatoNN’s resistance to ToBRFV is effective at around 22°C (71.6°F) but decreases at higher temperatures, such as 30°C (86°F). This temperature sensitivity is characteristic of several plant resistance genes.

“As we look at the possible virus-resistant tomato cultivars, it is important to understand the role that temperature plays in production,” Ling notes, highlighting its significant influence on host-pathogen interactions. Further study is required to fully understand temperature’s role in tomatoNN’s genetic resistance.

Implications for the Industry

These findings represent a significant step toward developing new solutions for ToBRFV control. “The results described in this paper highlight the significant potential of using the tomatoNN line to breed tomato cultivars resistant to ToBRFV and offers a new approach to managing this important disease for a beloved food staple,” states Ling.

This collaborative research, involving the University of California, Berkeley; University of California, Davis; and Iowa State University, opens avenues for breeders to integrate this valuable resistance into future commercial tomato varieties, enhancing crop protection and contributing to global tomato supply stability.  

Reference: Zhou, J., Gilliard, A., Tung, J., Dinesh-Kumar, S.P., Whitham, S.A., Baker, B. and Ling, K.-S. (2025), The N gene protects tomato plants from tomato brown rugose fruit virus infection. Plant Biotechnol. J.

DOI:  https://doi.org/10.1111/pbi.70237

Sources : Genetic literacy project, HortiDaily, Plant Biotechnology Journal