Mapping and characterization of wheat stem rust resistance genes SrTm5 and Sr60 from Triticum monococcum

Abstract

Key messageThe new stem rust resistance gene Sr60 was fine-mapped to the distal region of chromosome arm 5AmS, and the TTKSK-effective gene SrTm5 could be a new allele of Sr22. AbstractThe emergence and spread of new virulent races of the wheat stem rust pathogen (Puccinia graminis f. sp. tritici; Pgt), including the Ug99 race group, is a serious threat to global wheat production. In this study, we mapped and characterized two stem rust resistance genes from diploid wheat Triticum monococcum accession PI 306540. We mapped SrTm5, a previously postulated gene effective to Ug99, on chromosome arm 7AmL, completely linked to Sr22. SrTm5 displayed a different race specificity compared to Sr22 indicating that they are distinct. Sequencing of the Sr22 homolog in PI 306540 revealed a novel haplotype. Characterization of the segregating populations with Pgt race QFCSC revealed an additional resistance gene on chromosome arm 5AmS that was assigned the official name Sr60. This gene was also effective against races QTHJC and SCCSC but not against TTKSK (a Ug99 group race). Using two large mapping populations (4046 gametes), we mapped Sr60 within a 0.44 cM interval flanked by sequenced-based markers GH724575 and CJ942731. These two markers delimit a 54.6-kb region in Brachypodium distachyon chromosome 4 and a 430-kb region in the Chinese Spring reference genome. Both regions include a leucine-rich repeat protein kinase (LRRK123.1) that represents a potential candidate gene. Three CC–NBS–LRR genes were found in the colinear Brachypodium region but not in the wheat genome. We are currently developing a Bacterial Artificial Chromosome library of PI 306540 to determine which of these candidate genes are present in the T. monococcum genome and to complete the cloning of Sr60.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-017-3024-z) contains supplementary material, which is available to authorized users.

Genome-wide association mapping for resistance to leaf, stem, and yellow rusts of common wheat under field conditions of South Kazakhstan

“…Several experiments were conducted in Kazakhstan to search for sources of SR resistance in wheat germplasm ( Kokhmetova & Atishova, 2012 ; Shamanin et al, 2016 ; Rsaliyev & Rsaliyev, 2018 ). Nearly 60 Sr genes have been identified and cloned in wheat and its wild relatives ( Chen et al, 2018 ). The highly virulent race Ug99 ( Sr31 ) is not found in Kazakhstan.…”

“…The search for additional sources of resistance to rust diseases can be conducted using extensive germplasm collections representing different genetic backgrounds and origins ( Kokhmetova et al, 2011 ; Badoni et al, 2017 ; Kumar et al, 2019 ). Linkage mapping has been commonly used to identify QTLs associated with resistance to SR ( Wang et al, 2015 ; Chen et al, 2018 ), LR ( Xue et al, 2018 ; Kthiri et al, 2018 ), and YR ( Zeng et al, 2019 ). This method was also successfully applied in QTL mapping for LR and SR resistance in Kazakhstan ( Genievskaya et al, 2019 ).…”

QTL Mapping for Adult Plant Resistance to Stripe Rust in Wheat line "Guixie 3"

“…The NBS domain binds to ATP or GTP to play a key role in plant disease resistance. Currently, multiple wheat NBS-LRR genes have been identi ed and linked to disease resistance, such as Lr1 (Qiu et al 2007), Lr10 (Bozkurt et al 2007), Lr21 and Lr40 (Spielmeyer et al 2000), Sr35 (Saintenac et al 2013), Sr33 (Periyannan et al 2013), Sr60 (Chen et al 2018), and Yr10 (Bozkurt et al 2007). In the present study, we identify Qyr.gaas.2AS (cfd36~AX-110576889) and found a structural region (chr2A: 17411781_17601016) containing multiple NBS-LRRs and the WRKY transcription factor located near the cfd36 marker.…”

The wheat Sr22, Sr33, Sr35 and Sr45 genes confer resistance against stem rust in barley

“…In contrast to wheat, where 60 stem rust resistance genes have been described (McIntosh et al ., 2017; Chen, Guo et al ., 2018), only ten stem rust resistance genes have been reported in barley; these being Rpg1 (Brueggeman et al ., 2002; Powers and Hines, 1933; Steffenson, 1992), Rpg2 (Case et al ., 2018; Patterson et al ., 1957), Rpg3 (Case et al ., 2018; Jedel, 1990; Jedel et al ., 1989), rpg4 (Jin et al ., 1994), Rpg5 (Brueggeman et al ., 2008; Sun and Steffenson, 2005; Sun et al ., 1996), rpg6 (Fetch et al ., 2009), Rpg7 (Henningsen and Steffenson, 2018), rpgBH (Steffenson et al ., 1984; Sun and Steffenson, 2005), RpgU (Fox and Harder, 1995), and an undesignated one from accession Skinless (Luig, 1957). Rpg1 is the most widely deployed amongst these genes due to its broad‐spectrum resistance which has remained effective for over 70 years (Brueggeman et al ., 2002; Steffenson, 1992).…”