Wild relatives of domesticated crop species harbor multiple, diverse, disease resistance (R) genes that could be used to engineer sustainable disease control. However, breeding R genes into crop lines often requires long breeding timelines of 5-15 years to break linkage between R genes and deleterious alleles (linkage drag). Further, when R genes are bred one at a time into crop lines, the protection that they confer is often overcome within a few seasons by pathogen evolution. If several cloned R genes were available, it would be possible to pyramid R genes in a crop, which might provide more durable resistance. We describe a three-step method (MutRenSeq)-that combines chemical mutagenesis with exome capture and sequencing for rapid R gene cloning. We applied MutRenSeq to clone stem rust resistance genes Sr22 and Sr45 from hexaploid bread wheat. MutRenSeq can be applied to other commercially relevant crops and their relatives, including, for example, pea, bean, barley, oat, rye, rice and maize.
Bibliographical noteFunding Information:
This research was supported by funds from the Gatsby Charitable Foundation, UK; Two Blades Foundation, USA; Biotechnology and Biological Sciences Research Council, UK; Borlaug Global Rust Initiative (BGRI) Durable Rust Resistance in Wheat (DRRW) Project (administered by Cornell University with a grant from the Bill & Melinda Gates Foundation and the UK Department for International Development); USDA-ARS National Plant Disease Recovery System; Grains Research and Development Corporation, Australia; and a fellowship to A.H. from Universiti Putra Malaysia (UPM), Malaysia. We are grateful to colleagues in The Sainsbury Laboratory and the Two Blades Foundation for helpful discussions. This research was supported in part by the NBI Computing infrastructure for Science (CiS) group and Dan MacLean's group by providing computational infrastructure.