pubmed.ncbi.nlm.nih.gov

Aegilops sharonensis genome-assisted identification of stem rust resistance gene Sr62 - PubMed

  • ️Sat Jan 01 2022

. 2022 Mar 25;13(1):1607.

doi: 10.1038/s41467-022-29132-8.

Guotai Yu  1   2   3 , Nicolas Champouret  5   6 , Burkhard Steuernagel  1 , Matthew J Moscou  5 , Inmaculada Hernández-Pinzón  5 , Phon Green  5 , Sadiye Hayta  1 , Mark Smedley  1 , Wendy Harwood  1 , Ngonidzashe Kangara  1 , Yajuan Yue  1 , Catherine Gardener  1 , Mark J Banfield  1 , Pablo D Olivera  4 , Cole Welchin  4 , Jamie Simmons  4 , Eitan Millet  7 , Anna Minz-Dub  7 , Moshe Ronen  7 , Raz Avni  7   8   9 , Amir Sharon  8 , Mehran Patpour  10 , Annemarie F Justesen  10 , Murukarthick Jayakodi  11 , Axel Himmelbach  11 , Nils Stein  11   12 , Shuangye Wu  13 , Jesse Poland  13 , Jennifer Ens  14 , Curtis Pozniak  14 , Miroslava Karafiátová  15 , István Molnár  15   16 , Jaroslav Doležel  15 , Eric R Ward  5   17   18 , T Lynne Reuber  17   19 , Jonathan D G Jones  5 , Martin Mascher  11   20 , Brian J Steffenson  21 , Brande B H Wulff  22   23   24

Affiliations

Aegilops sharonensis genome-assisted identification of stem rust resistance gene Sr62

Guotai Yu et al. Nat Commun. 2022.

Abstract

The wild relatives and progenitors of wheat have been widely used as sources of disease resistance (R) genes. Molecular identification and characterization of these R genes facilitates their manipulation and tracking in breeding programmes. Here, we develop a reference-quality genome assembly of the wild diploid wheat relative Aegilops sharonensis and use positional mapping, mutagenesis, RNA-Seq and transgenesis to identify the stem rust resistance gene Sr62, which has also been transferred to common wheat. This gene encodes a tandem kinase, homologues of which exist across multiple taxa in the plant kingdom. Stable Sr62 transgenic wheat lines show high levels of resistance against diverse isolates of the stem rust pathogen, highlighting the utility of Sr62 for deployment as part of a polygenic stack to maximize the durability of stem rust resistance.

© 2022. The Author(s).

PubMed Disclaimer

Conflict of interest statement

G.Y. and B.B.H.W. are inventors on a US provisional patent application 63/250,413 filed by 2Blades and relating to the use of Sr62 for stem rust resistance in transgenic wheat. T.L.R. and E.R.W. were employed by the 2Blades Foundation, and E.R.W. continues to serve on the 2Blades board. Both were involved in the conceptualization and design of the research presented, which was cofunded by the 2Blades Foundation. The remaining authors declare no competing interests.

Figures

Fig. 1
Fig. 1. Positional mapping restricts Sr62 to a 480 kb interval on chromosome 1Ssh.

a Wheat–Ae. sharonensis translocation chromosomes and Ae. sharonensis chromosome 1Ssh. b Genetic map of the region harbouring Sr62 on the short arm of Ae. sharonensis chromosome 1Ssh. c Physical map of the region around Sr62. d Genes in the interval genetically delimiting the presence of Sr62. WTK is presumably an ortholog of Pm24.

Fig. 2
Fig. 2. Candidate gene identification by mutagenesis and transcriptome sequencing (MutRNA-Seq).

RNA-Seq reads from the wild-type parent and independently derived EMS mutants are mapped to a reference genome sequence. Annotated genes are inspected (within a mapping interval, if available) for a gene exhibiting a preponderance of single-nucleotide variants (SNVs, red dots) across the mutants.

Fig. 3
Fig. 3. Functional validation of Sr62 by EMS mutagenesis and transformation into wheat.

a Structure of Sr62, with predicted nucleotide change caused by EMS-derived loss-of-function mutations. Boxes represent exons and lines represent introns with white boxes representing untranslated regions and black boxes representing the predicted open reading frame. The 11.4-kb portion of the third intron excluded from the binary construct is indicated. b Schematic representation of the Sr62 protein, with the position of the two protein kinase domains and the predicted amino-acid changes caused by the EMS mutations indicated. c The Sr62 sequence used for transformation of wheat cultivar Fielder. CDS, coding DNA sequence. d Reactions of three homozygous independent transgenic lines to four Pgt isolates. The copy number of the hygromycin selectable marker in T0 plants is indicated.

Fig. 4
Fig. 4. Phylogenetic relationship between tandem kinases from cereal crop and wild grasses.

A total of 99 predicted tandem kinases were retrieved from the genomes of bread wheat, durum wheat, maize, barley, sorghum, rice, Ae. tauschii and Ae. sharonensis, along with the five cloned tandem kinase disease resistance genes. Phylogenetic clades and subclades are indicated by different colours and labelled with numbers. a Phylogeny based on the whole tandem kinase coding sequence. b Phylogeny based on the individual protein kinase domain coding sequences.

Fig. 5
Fig. 5. Synteny around Sr62.

Genomic regions containing genes orthologous to Sr62 along with surrounding genes reveal micro-synteny. The syntenic block is well conserved within the Triticum spp., Aegilops spp., and barley, but appears to be absent from Brachypodium, rice, sorghum and maize. The synteny alignment was generated through Gramene, except for Ae. sharonensis, which was added manually.

Similar articles

Cited by

References

    1. Peterson, P. D. Stem Rust of Wheat: From Ancient Enemy to Modern Foe. Am. Phytopathol. Soc. (APS Press, St. Paul, 2001).
    1. Le Roux J, Rijkenberg FH. Occurrence and pathogenicity of Puccinia graminis f. sp. tritici in South Africa during the period 1981–1985. Phytophylactica. 1987;19:467–472.
    1. Addai, D. et al Potential economic impacts of the wheat stem rust strain Ug99 in Australia, ABARES research report, prepared for the Plant Biosecurity Branch, Department of Agriculture and Water Resources, Canberra (2018).
    1. Pretorius ZA, Singh RP, Wagoire WW, Payne TS. Detection of virulence to wheat stem rust resistance gene Sr31 in Puccinia graminis f. sp. tritici in Uganda. Plant Dis. 2000;84:203. doi: 10.1094/PDIS.2000.84.2.203B. - DOI - PubMed
    1. Jin Y, et al. Detection of virulence to resistance gene Sr24 within race TTKS of Puccinia graminis f. sp. tritici. Plant Dis. 2008;92:923–926. doi: 10.1094/PDIS-92-6-0923. - DOI - PubMed

Publication types

MeSH terms