Identification and characterization of new sources of resistance to tomato brown rugose fruit virus (ToBRFV) to generate resistant tomato plants

• Applicant: Dr. Khalid Amari Baba
• Subject Area: Plant Breeding and Plant Pathology ; Virology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 533713219

Tomato (Solanum lycopersicum L.), after potato, is the most important vegetable crop in the world, with a total world production of approximately 186.821 million tons of fresh fruit. Viruses are among the pathogens affecting significantly tomato production worldwide. The genus Tobamovirus includes, among other viruses, tobacco mosaic virus (TMV) and tomato mosaic virus (ToMV), which represent a threat to tomato plants in particular and Solanaceae in general. Resistance genes against tobamoviruses, namely Tm-1, Tm-2, and Tm-22 have been identified and used in breeding programs, conferring a long-lasting resistance. However, a new tobamovirus named tomato brown rugose fruit virus (ToBRFV), infecting tomatoes and peppers was identified in first Israel and Jordan and is spreading worldwide, including in Germany. ToBRFV seriously affects tomato production; unfortunately, ToBRFV has overcome the long‐lasting resistance genes (Tm‐1, Tm‐2, and Tm‐22). The EPPO added ToBRFV to the EPPO alert list and the list of quarantine organisms. Therefore, it is urgent to identify new sources for resistance and introgression of such resistance in commercial hybrids or varieties through breeding programs. For a successful infection, viruses interact with host factors termed susceptibility factors at different stages of the infection. The proposed project aims to identify host genes termed susceptibility (S) genes, necessary for ToBRFV infection in particular and tobamoviruses in general. We will identify and functionally characterize such genes to develop novel strategies for virus control by the targeted modulation of these genes. To do that, we will use the host Nicotiana benthamiana, stably expressing a GFP-tagged dsRNA-binding protein (B2:GFP) to pull down viral dsRNA and to identify by mass spectroscopy, associated host proteins involved in replication in planta upon infection with ToBRFV or other tobamoviruses such as TMV and ToMV. CRISPR-Cas method will be used to modulate the expression of candidate S genes in tomato plants and assess the role of such S genes in resistance to ToBRFV in particular and tobamoviruses in general. The results obtained in the proposed project will constitute major progress in the field of host-virus interactions. We expect scientific advances to shed light on a better understanding of the molecular dialogue between viruses and host cells and help shape plant protection and resistance strategies for engineering broad-spectrum antiviral resistance against ToBRFV in particular and tobamoviruses in general.

• DFG Programme: Research Grants