Three previously characterized resistances to yellow rust are encoded by a single locusWtk1

Abstract

The wild emmer wheat (Triticum turgidum ssp. dicoccoides; WEW) yellow (stripe) rust resistance genes Yr15, YrG303 and YrH52 were discovered in natural populations from different geographic locations. They all localize to chromosome 1B but were thought to be non-allelic based on differences in resistance response. We recently cloned Yr15 as a Wheat Tandem Kinase 1 (WTK1) and showed here that these three resistance loci co-segregate in fine-mapping populations and share identical full-length genomic sequence of functional Wtk1. Independent EMS mutagenized susceptible yrG303 and yrH52 lines carried single nucleotide mutations in Wtk1 that disrupted function. A comparison of the mutations for yr15, yrG303 and yrH52 mutants showed that while key conserved residues were intact, other conserved regions in critical kinase subdomains were frequently affected. Thus, we concluded that Yr15-, YrG303- and YrH52-mediated resistances to yellow rust are encoded by a single locus Wtk1. Introgression of Wtk1 into multiple genetic backgrounds resulted in variable phenotypic responses, confirming that Wtk1-mediated resistance is part of a complex immune response network. WEW natural populations subjected to natural selection and adaptation have potential to serve as a good source for evolutionary studies of different traits and multifaceted gene networks.HighlightWe demonstrate that Yr15, YrG303 and YrH52 resistances are encoded by the Wtk1 locus, but express variable resistance responses to yellow rust in a genetic background dependent manner.

Novel stripe rust all‐stage resistance loci identified in a worldwide collection of durum wheat using genome‐wide association mapping

“…dicoccoides ). Based on Yr15 linked markers (Klymiuk et al., 2020), the remaining three QTL on chromosome 1B in this study were distantly located (100–280 Mb) from Yr15 . QYrdu.1B‐4 (337–339 Mb) from this study was mapped within the genomic region of Yr24 / Yr2 6 (Wu et al., 2018) and Yr64 (Cheng et al., 2014).…”

“…On chromosome 1B, we identified four stripe rust resistance QTL at 52, 165, 171, and 337–339 Mb. Chromosome 1B harbors a cluster of Yr genes (Cheng et al., 2014; Wu et al., 2018), and some of them originated from tetraploid wheat, including Yr15 / YrH52 (Peng et al., 1999; Klymiuk et al., 2020), Yr24 / Yr26 (Chague et al., 1999; Ma et al., 2001; G. Li et al., 2006), and Yr64 and Yr65 (Cheng et al., 2014). QYrdu.1B‐1 (52 Mb) identified in this study was mapped at 7 Mb distal from Yr15 flanking SNP marker RAC875_c826_839 (Klymiuk et al., 2020).…”

“…Chromosome 1B harbors a cluster of Yr genes (Cheng et al., 2014; Wu et al., 2018), and some of them originated from tetraploid wheat, including Yr15 / YrH52 (Peng et al., 1999; Klymiuk et al., 2020), Yr24 / Yr26 (Chague et al., 1999; Ma et al., 2001; G. Li et al., 2006), and Yr64 and Yr65 (Cheng et al., 2014). QYrdu.1B‐1 (52 Mb) identified in this study was mapped at 7 Mb distal from Yr15 flanking SNP marker RAC875_c826_839 (Klymiuk et al., 2020). Therefore, QYrdu.1B‐1 could be Yr15 that was introgressed into durum wheat cultivars from wild emmer wheat ( T. turgidum L. ssp.…”

A Post-Haustorial Defense Mechanism is Mediated by the Powdery Mildew Resistance Gene, PmG3M, Derived from Wild Emmer Wheat

“…The current histopathology study is part of a long-term project aiming to clone and characterize powdery mildew and stripe rust resistance genes derived from wild emmer wheat by using the map-based cloning approach, as we recently demonstrated for the cloning of Yr15 [ 14 , 20 ]. Previously, we localized PmG3M to chromosome 6B using the G305-3M × LDN mapping population [ 12 ].…”

“…Fluorescence microscopy of Bgt structures was performed using wheat germ agglutinin (WGA; a lectin that binds specifically to β (1→4)-N-acetyl-D-glucosamine, i.e., chitin) conjugated with a fluorescent dye, according to Dawson et al [ 43 ] and Klymiuk et al [ 14 , 20 ], with slight modifications. Leaf segments (primary leaf, 5 cm long) were sampled at 4, 8, 12, 18, 24, 32, 48, 72, 96, 120, 144, 168 and 240 h post inoculation (hpi) with Bgt spores.…”