Using field pathogenomics to study wheat yellow rust dispersal and population dynamics at a national and international scale

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The impact of this proposal relates to the detailed understanding of the population structure of a major wheat pathogen, yellow rust. Project outputs will impact on wheat producers, plant breeders, regulatory and testing authorities, and pathogen surveillance projects. As yellow rust is a global disease, project outcomes will have national and far-reaching international impacts. In the UK, yellow rust control is reliant on a combination of resistance and fungicide use. The latter is under increasing pressure from withdrawal of actives, or tightening regulations on use. The importance of host plant resistance is therefore likely to increase, but it must be at a reasonably high level, and reliable. This project will increase, by several orders of magnitude, the ability of surveillance projects such as the UK Cereal Pathogen Virulence Survey, to detect and characterise damaging yellow rust variants at an early stage. Such information will have immediate impacts for growers, enabling them to change variety choice, or react in season with different fungicide programmes to counter epidemics. A detailed regional understanding of virulence structure will enhance the potential for diversification of varieties, where different resistances could be deployed on a landscape scale to decrease inoculum pressure and preserve the durability of resistance traits. Plant breeders will benefit from earlier and more detailed knowledge of pathogen population structure so that alternative resistance sources can be incorporated into breeding material, and sudden "breakdown" of resistance can be avoided during commercialisation. Testing and regulatory authorities will benefit by having improved information on pathotypes for use in testing programmes. Surveillance projects, such as UKCPVS, would change approaches to use the new technologies devised in the project, becoming more efficient and of greater value to end users. The project outputs will be tested immediately in this survey work at the end of the grant, and could be implemented in routine work within a further three year period. Plant breeders would also benefit in the short term as more comprehensive and in depth undertsanding of yellow rust population structures would be immediately available.

Though targeted at yellow rust in this project, field pathogenomics could be applied to many other plant pathogens which have variable pathotypes interacting with host resistance. Virulence monitoring in cereal rusts is an international effort, with research in the US, China, Australia, Africa and Europe, and the techniques and sampling strategies investigated in the current proposal would be of value wherever cereal rusts occur.