The resistance protein Rz2 from Beta vulgaris recognises the avirulence protein triple gene block I of beet necrotic yellow vein virus - characterisation of the interaction and assessment of resistance stability

• Applicant: Professor Dr. Mark Varrelmann
• Subject Area: Plant Breeding and Plant Pathology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 519632024

The DFG research project intends to characterise more precisely the nature of the interaction between TGB1 and Rz2 in order to make an important contribution to a better understanding of antiviral resistance mechanisms in a hitherto unstudied plant species with extremely broad recognition. Since Rz2 is also functional in the experimental host N. benthamiana, it can be excluded that species-specific factors from B. vulgaris are necessary for recognition. The object of the study is, on the one hand, the functional characterisation of the individual domains of Rz2 and the elucidation of possible intramolecular interactions. For a better understanding of the interaction, the characterisation of the localisation on the subcellular level is also necessary. This includes, among other things, the detection of a subcellular co-localisation of both proteins that is necessary for the interaction. This work is intended to provide a deeper understanding of how Rz2 functions. The complex signalling cascade of the resistance mechanism from the recognition of TGB1 to the triggering of an ER/HR by Rz2 consists of many protein interactions; however, there have been few studies with the model pathogen systems on the entire interaction network so far. Novel proximity labelling of intercellular protein interaction partners will be applied to Rz2 to identify and subsequently validate key interaction partners of recognition and signal transduction. Due to the increasing cultivation of Rz2 resistant varieties, a strong selection pressure is exerted on the soil-borne BNYVV populations, which promotes the emergence of resistance-breaking variants. Due to the great importance of Rz2 for sugar beet cultivation, the durability of resistance is absolutely essential. Therefore, another project goal is to evaluate Rz2 resistance stability. For this purpose, different experimental approaches under artificial and natural selection pressure will be applied to identify resistance breaking TGB1 variants in BNYVV populations. These results will improve our overall understanding of viral evolution for adaptation to plant resistance factors.

• DFG Programme: Research Grants
• Co-Investigator: Dr. Sebastian Liebe