Identification of genes in tomato and other crops for resistance or susceptibility to Verticillium wilt
Verticillium dahliae is among the world’s most notorious plant pathogens, causing vascular wilt disease in a wide range of hosts. Currently, only one resistance gene against V. dahliae, Ve1, has been identified. As race 2 strains of V. dahliae are not recognized by Ve1, additional resistance sources are required to control these strains.
This project aims at mapping of new resistance genes (R-genes) and finding susceptibility genes (S-genes) to this pathogen, particularly in tomato, and applying that knowledge to other crops too.
The overall aim of this project is to identify and study different layers of resistance to Verticillium wilt, using both R-genes and impaired S-genes, with the focus on resistance to race 2 strains of V. dahliae in tomato and both race 1 and race 2 resistance in other crops.
The objectives of this project are:
1. Identification of R-genes to race 2 strains of V. dahliae in tomato;
2. Identification of impaired S-genes to V. dahliae in tomato, leading to resistance;
3. Identification and functional characterisation of orthologous S-genes in other crops such as eggplant, lettuce and brassica (partly performed in the companies);
4. Elucidation of the mode-of-action and mechanism and possible negative side-effects of V. dahliae resistance from the identified R-genes and impaired S-genes;
5. Directed gene editing of S-genes in tomato, for optimizing resistance, without negative side effects on plant development.
This project fits under the mission “Keytechnologies”, in particular Biotechnology and Breeding. The knowledge of the genes that are involved in resistance help to design strategies to “create” resistances by mutagenesis or searching for natural variation in the identified genes. Also, it fits under mission D “Valued, healthy and safe food”. Natural Verticillium resistance genes make plant yield less dependent of the use of fungicides and decrease concomitant environmental pressure.
Healthy eating starts with appreciating healthy food. Consumers should not associate fruit with chemical residues from fungicides. Therefore, it is important that alternatives to protect the plants against pathogens and the best way has been invented by nature itself.
This project aims to identify the natural resistance genes that can be crossed into cultivars and protect against the soil fungus Verticillium. In addition, resistant plants prevent development and spreading of the pathogen which also keeps the soil clean. Clean soils do not have to be sterilized and as such also decrease the requirement of disinfecting chemicals which is good for the environment and also for the farmer. As the involved seed companies are very internationally oriented and have worldwide breeding programs, the R-genes and impaired S-genes that are detected in this project will be deployed in breeding programs of the project partners in many parts of the world.
Therefore, this project belongs to the PPS “Better plants for new demands”, where it contributes to the subtheme “Plant Breeding and Seed Technology” and “Plant Health”.
We intend to obtain the following results:
• Identify wild tomato accessions with resistance to V. dahlia in the first year of the project
• Develop DNA-markers associated with the V. dahliae resistance genes in the wild tomato accessions before the end of the project
• Characterize a set of candidate S genes by testing RNAi and gene edited tomato plants before the end of the project
• Knowledge on modes-of-action of the identified R-gene and S-genes
• Insight in possible negative side-effects of impaired S-genes