Institut für die Sicherheit biotechnologischer Verfahren bei Pflanzen
Viruses pose a significant threat to tomato production, as many are easily transmissible and can cause considerable economic losses. Current losses in tomato production due to virus infection are between 70 and 95%. Tomato Brown Rugose Fruit Virus (ToBRFV) is a new tobamovirus that infects tomato and bell pepper plants all over the world - including Germany. ToBRFV has overcome the long-standing gene-mediated resistance to tobamoviruses. ToBRFV is particularly problematic in tomato and bell pepper cultivation, as infections are spread via seeds, grafts, cuttings and seedlings, but also via fresh fruit. As soon as the virus has been introduced into an area, the infected plants must be destroyed and strict hygiene controls must be carried out. In order to prevent the introduction and spread of the virus in Europe, the European and Mediterranean Plant Protection Organization (EPPO) has included ToBRFV in the EPPO warning list (Commission Implementing Decision EU 2019/1615) and in the list of quarantine organisms (Commission Regulation EU 2019/2072). There is a risk that the impact of ToBRFV on tomato and bell pepper production will be exacerbated by higher temperatures due to global warming. Therefore, there is an urgent need to identify new resistance genes and introduce them into commercial hybrids or varieties through breeding programs. However, the screening of existing breeding material for resistance to ToBRFV has so far been unsuccessful. In order to infect a plant, viruses, like other pathogens, use specific host factors (usually proteins). These host factors are based on "susceptibility genes" (S-genes), and their absence prevents infection. S genes are therefore considered good target genes for achieving resistance or tolerance through mutation. However, S genes also have a function for the plants. Modulation of the expression of such genes can therefore cause undesirable, negative and/or pleiotropic effects in the plant, such as developmental defects, yield reduction or even increased susceptibility to other pathogens. The aim of this project is to investigate the role of these S genes in virus infection and whether changes (silencing) of these genes can lead to resistance or tolerance of the plant to ToBRFV and/or to undesirable side effects. The project will use the CRISPR/Cas system to down-regulate or switch off the potential susceptibility genes and investigate the interaction with the virus infection. The project identifies and characterizes S-gene candidates and evaluates possible side effects.
German Research Foundation
