Associate Professor University of Amsterdam Amsterdam, Noord-Holland, Netherlands
Identification, characterization and subsequently introgression of natural genetic resistances into elite cultivars is one of the major strategies in sustainable plant breeding nowadays. As one can imagine this process is tedious, laborious and time consuming. The complexity of this work increases when more and more resistances against novel emerging pathogens, for example due to changing climates, must be combined with existing ones. Often these plant resistances are based on single dominant resistance genes of the NLR class family. Plant viruses, especially RNA based ones that rely on reverse transcription of their genome, present a group of pathogens with high variability and therefore possess high and fast adaptability to novel resistances introduced in the field. TSWV for example with its remarkably broad host range, estimated to include over 1000 plant species, has overcome the two cloned CC-NLR resistance genes Sw5b(tomato) and Tsw (pepper) by single amino acid changes in the effector proteins NSm and NSs respectively. In this work we propose a strategy for untargeted molecular evolution of NLR associated functional domains known to interact with viral effector proteins. This combined with a high-throughput gain-of-function screening method based on Ribosome Display and in vivo tests using leaf discs of Nicotiana benthamiana should enable the rapid identification of adapted NLR genes regaining resistance towards breaking isolates of TSWV.
