Creation and judicious application of a wheat resistance gene atlas

Abstract

Disease resistance (R) gene cloning in wheat (Triticum aestivum) has been accelerated by the recent surge of genomic resources, facilitated by advances in sequencing technologies and bioinformatics. However, with the challenges of population growth and climate change ahead of us, it is vital not only to clone and functionally characterise a few handfuls R genes, but to do so at an agroecologically relevant scale. Pathogen populations are continually changing, and breeders must have tools and resources available to respond to those changes as quickly as possible if we are to safeguard our daily bread. To meet this challenge, we propose the creation of a wheat R gene atlas by an international community of researchers and breeders. The atlas would take the form of an online directory from which sources of resistance could be identified and deployed to achieve more durable resistance to the major wheat pathogens, such as wheat rusts, blotch diseases, powdery mildew and wheat blast. We present a costed proposal detailing how the interacting molecular components governing disease resistance could be captured from both the host and pathogen through biparental mapping, mutational genomics and whole-genome association genetics. We explore options for the effective configuration and genotyping of diversity panels of hexaploid and tetraploid wheat, as well as their wild relatives and major pathogens, and discuss how the atlas could inform a dynamic, durable approach to R gene deployment. Set against the current magnitude of wheat yield losses worldwide (recently estimated at 209 million tonnes each year; Savary et al., 2019a), this endeavour presents one route for bringing R genes from the lab to the field at a considerable speed and quantity.