Generation of Loss-of-Function Mutants for Wheat Rust Disease Resistance Gene Cloning

Abstract

One of the most important tools to identify and validate rust resistance gene function is by producing loss-of-function mutants. Mutants can be produced using irradiation, chemicals, and insertions. Among all the mutagens, ethyl methanesulfonate (EMS) and sodium azide are most favored because of the ease of use and generation of random point mutations in the genome. The mutants so produced facilitate the isolation, identification and cloning of rust resistance genes. In this chapter we describe a protocol for seed mutagenesis of wheat with EMS and sodium azide.

Application of Genomics Tools in Wheat Breeding to Attain Durable Rust Resistance

“…a ) on chromosome 2H from cultivated barley ( Hordeum vulgare ) cv Sudan was also rapidly cloned by combining this approach with genetic mapping. The successful application of this approach would need prior information on, chromosome location of the target gene ( Dracatos et al., 2019 ; Zhang et al., 2020 ), large mutant populations to identify the target genes among five to six mutants ( Mago et al., 2017 ; Dinh et al., 2020 ) and isolation of individual chromosomes ( Periyannan, 2018 ).…”

The Coiled-Coil NLR Rph1, Confers Leaf Rust Resistance in Barley Cultivar Sudan

“…A limitation of this approach is the high number of mutants (;5 in barley, ;6 in wheat) necessary to identify a single candidate gene (Sánchez-Martín et al, 2016). This requires the generation and screening of a large mutant population, typically numbering several thousand individuals (Mago et al, 2017), in particular in barley (a diploid) where the tolerated mutation density is approximately seven times less than that in hexaploid wheat (Uauy et al, 2017). The requirement for many mutants for unambiguous gene identification can be mitigated if combining chromosome flow sorting with positional mapping (Thind et al, 2017).…”