7/4/2023 0 Comments Kinase protein scaffoldThe dominant resistance gene Sr43 was introgressed into chromosome 7D of hexaploid wheat (Fig. Here, we cloned the stem rust resistance gene Sr43, which was transferred from tall wheatgrass ( Thinopyrum elongatum) into bread wheat 45 years ago 2, 3. This genomic innovation resulted in resistance against phylogenetically distinct fungal pathogens spanning the ~300 million-year-old ascomycete/basidiomycete divide. However, the fusion events that gave rise to these genes, far from being rare and isolated, happened many times between different classes of kinases and spawned diverse combinations 10, 12. These kinase fusion protein-encoding resistance genes appear to be unique to the Triticeae, the clade of grasses that arose 12 million years ago and encompasses the cereals wheat, rye ( Secale cereale) and barley ( Hordeum vulgare) 23. Other resistance genes offer some variation to this architecture with protein kinases fused to a steroidogenic acute regulatory protein-related lipid transfer domain ( Yr36) 16, a C2 domain and a multitransmembrane region ( Pm4) 17, a major sperm protein ( Snn3) 18, an NLR ( Tsn1, Rpg5 and Sm1) 19, 20, 21 and a von Willebrand factor type A domain ( Lr9) 22. These tandem kinase genes include Rpg1, Yr15, Sr60, Sr62, Pm24, WTK4 and Rwt4 (refs. A new group of resistance genes has recently come to light, whose members encode two protein kinases fused as one protein. Most of the ~291 plant disease resistance genes cloned to date encode either intracellular receptors of the nucleotide-binding and leucine-rich repeat (NLR) class or extracellular membrane-anchored receptor-like proteins (RLPs, called RLKs when they contain an intracellular kinase) (Supplementary Table 1) 1, 8. Cloning individual resistance genes would enable their introduction as genetically modified polygene stacks, which are likely to provide more durable resistance 7. Moreover, single resistance genes tend to be rapidly overcome by the emergence of resistance-breaking pathogen strains 6. However, the deployment of these interspecific resistance genes is often hampered by linkage drag, that is, the cointroduction of deleterious alleles from linked genes. Notably, more than 200 of the 467 currently designated resistance genes in cultivated bread wheat have their origin outside the bread wheat gene pool 1. For over 100 years, breeders have conducted numerous crosses to enrich the wheat gene pool with resistance genes. The deployment of genetic variation for disease resistance is a sustainable and environmentally friendly way to protect wheat crops 5. Worldwide, ~20% of projected bread wheat ( Triticum aestivum) production is lost to pests and diseases every year 4. The wheat stem rust resistance gene Sr43 encodes an unusual protein kinase
0 Comments
Leave a Reply. |