Tomato brown rugose fruit virus (ToBRFV) is a pathogenic virus of tomato that has emerged in recent years and has become a serious problem worldwide. A new control method has been sought as the existing resistance genes were not effective against ToBRFV. National Agriculture and Food Research Organization (NARO) and Takii & Co., Ltd. have demonstrated by genome editing technology that tomatoes with strong resistance to ToBRFV can be produced by disabling the genes of tomato that the virus utilizes for their multiplication. This research result is expected to contribute to the suppression of ToBRFV if the development and popularization of ToBRFV resistant tomato cultivars progresses.
Tomato brown rugose fruit virus (ToBRFV), which causes brown spots and wrinkles in fruits was first discovered in the Middle East in 2014, and it infects tomatoes and peppers. For the tomatoes infected with ToBRFV, yield was decreased by 30-70% due to poor growth, and the quality of the harvested fruits was also reduced. The cost of hygiene management work such as replacement of contaminated soil and quarantine will also be enormous. Although the outbreak of ToBRFV has not yet occurred in Japan, it is spreading rapidly to many regions around the world (reported in 30 countries as of February 2022), and is a major concern for the stable supply of tomatoes internationally. Existing virus-resistant tomato cultivars were susceptible to ToBRFV, so a new control method has been sought around the world.
The research group has demonstrated with genome editing technology that tomatoes with strong ToBRFV resistance can be produced by disabling the genes of tomatoes that the virus uses for their multiplication. This tomato showed resistance not only to ToBRFV but also to closely related tomato mosaic virus, etc., indicating that it is effective against multiple important viral diseases simultaneously. Generally, if a plant's original genes are disabled, it may have unintended adverse effects on growth. However, the ToBRFV-resistant tomatoes produced in this study grew and set normally under the environmental conditions of the laboratory. From the above research results, this method is considered to be extremely promising for imparting resistance to ToBRFV without significantly reducing the quality and yield of tomatoes.
Takii & Co., Ltd. is promoting the development of ToBRFV resistant tomato cultivars by the conventional breeding method while utilizing this knowledge.
Tomato brown rugose fruit virus resistance generated by quadruple knockout of homologs of TOBAMOVIRUS MULTIPLICATION1 in tomato. Masayuki Ishikawa, Tetsuya Yoshida, Momoko Matsuyama, Yusuke Kouzai, Akihito Kano, and Kazuhiro Ishibashi. Plant Physiology, published online. https://doi.org/10.1093/plphys/kiac103