Sources of Stem Rust Resistance in Cultivated and Wild Tetraploids

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Pablo Olivera, University of Minnesota

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Sources of Stem Rust Resistance in Cultivated and Wild Tetraploids

  1. 1. Sources of Stem Rust Resistance in Cultivated and Wild Tetraploids Pablo D. Olivera and Yue Jin University of Minnesota USDA-ARS Cereal Disease Laboratory
  2. 2. Contents •  Introduction - Pgt races at Debre Zeit durum nursery •  Resistance to stem rust in tetraploid wheats - durum and cultivated emmer - wild emmer and other cultivated tetraploids - genetics of resistance and mapping •  Resistance to stem rust in Aegilops ssp. •  Summary 2
  3. 3. Stem Rust Resistance in Durum ● Durum wheat of North America has a higher frequency of resistance to TTKSK (Ug99) than common wheat ● We postulated that resistance to TTKSK in durum is most likely due to Sr13 ● When durum resistant selections were evaluated in Debre Zeit (Ethiopia), many became susceptible to stem rust ● Hypothesis: stem rust races in Debre Zeit may possess a virulence combination that overcome the TTKSK resistance 3 Njoro Nursery
  4. 4. Durum Stem Rust Field Nursery •  Debre Zeit, Ethiopia •  Located in a major durum wheat growing area •  Two growing seasons Main season: July – October Off season: February - May Debre Zeit 4
  5. 5. Races Identified at Debre Zeit Nursery TRTTF Virulent on Sr13 and Sr9e Virulent on Sr36 and SrTmp Avirulent on Sr31 and Sr24 JRCQC Virulent on Sr13 and Sr9e Avirulent on Sr36 and SrTmp Avirulent on Sr31 and Sr24 JRCQC TRTTF TTKSK JRCQC TRTTF TTKSK Sr13 Sr9e Olivera et al., 2012. Plant Disease 96: 623-628 5
  6. 6. Tetraploids as a Source of Resistance Genes Gene Donor Relevance Sr2 Emmer Adult Plant Resistance Sr13 Emmer Main component of SR resistance in NA durum Effective against Ug99 Sr9e Emmer Main component of SR resistance in NA durum Ineffective against Ug99 Sr14, 17, 9d Emmer Sr12 Durum May play a role in Ug99 resistance in bread wheat 6
  7. 7. Genetic Resources ● The USDA – ARS National Small Grains Collection (NSGC) has an extensive collection of tetraploid wheats (Triticum turgidum ssp.) ~ 8300 durum ~ 2100 cultivated and wild tetraploids 7 ● Objectives: 1. Identify and characterize new sources of stem rust resistance in the T. turgidum collection deposited at NSGC 2. Elucidate the genetics of resistance and mapping of resistance genes
  8. 8. Tetraploids Evaluated Name Species Number Evaluations Durum T. turgidum ssp. durum 5,000 Adult - seedling Emmer T. turgidum ssp. dicoccum 359 Adult - seedling Wild emmer T. turgidum ssp. dicoccoides 880 Seedling Persian wheat T. turgidum ssp. carthlicum 77 Seedling Polish wheat T. turgidum ssp. polonicum 63 Seedling Oriental wheat T. turgidum ssp. turanicum 66 Seedling Poulard wheat T. turgidum ssp. turgidum 414 Seedling TOTAL 6,859 Accessions deposited at the NSGC (Aberdeen, ID) 8
  9. 9. Durum and Emmer - Phenotypic Evaluation Entries resistant to moderately resistant in Debre Zeit are evaluated in: Debre Zeit and St. Paul, MN in two growing seasons All entries evaluated in Debre Zeit (Ethiopia) stem rust nursery Entries resistant to moderately resistant in all field evaluations are evaluated at seedling stage against races: TTKSK (Kenya), TRTTF (Yemen), TTTTF (USA) Accessions resistant to race TTKSK are evaluated against: JRCQC, TKTT- (Ethiopia) TPMKC, RKQQC, RCRSC, QTHJC, QFCSC, MCCFC (USA) Durum 5,000 entries modern and old cultivars, breeding lines, landraces Emmer 359 entries Ethiopia, Europe, Caucasus, and Middle East 9
  10. 10. Stem Rust Field Nurseries Debre Zeit Inoculum 2009 - 2010: TTKSK + bulk of Ethiopian isolates (50:50) Inoculum 2011 - 2013: 100% bulk of Ethiopian isolates St. Paul Inoculum 2009 - 2013: TPMKC, RKQQC, RCRSC, QTHJC, QFCSC, MCCFC 10
  11. 11. Field Evaluation Durum Emmer # entries evaluated in Debre Zeit nursery 5,000 359 # (%) of entries resistant to moderately resistant 914 (18.3%) 164 (50.3%) # (%) entries R to MR in all Debre Zeit evaluations 298 (6.0%) 51 (14.2%) # (%) of entries R to MR in all field evaluations 252 (5.0%) 39 (10.8%) 11
  12. 12. Distribution of Resistant Entries 12 0 10 20 30 40 50 60 70 R R-MR MR-R MR MR-MS MS-MR MS Debre Zeit St. Paul #entries Infection Response
  13. 13. Origins of Resistant Durum Entries 13 Egypt, 27 Mexico, 50 Ethiopia, 44 USA, 32 Canada, 9 Others, 65 Turkey, 8 Italy, 8 Chile, 10
  14. 14. Seedling Evaluation Durum Emmer # accessions resistant in all field evaluations 252 39 # accessions resistant to race TTKSK at seedling 240 32 # accessions resistant to all races 133 28 # accessions susceptible against all races 9 4 14
  15. 15. Infection Types at Seedling Stage Emmer (T. turgidum ssp. dicoccoum) Durum wheat (T. turgidum ssp. durum) 15
  16. 16. Wild Emmer and Other Cultivated Tetraploids University of Minnesota - BSL3 facility All the accessions evaluated at SEEDLING STAGE against: TTKSK (Kenya), TRTTF (Yemen), TTTTF (USA) Accessions resistant to race TTKSK are evaluated against: JRCQC, TKTT- (Ethiopia) US races: TPMKC, RKQQC, RCRSC, QTHJC, QFCSC, MCCFC Location: Biosecurity Level 3 facility University of Minnesota Period: December 1st – March 31st
  17. 17. Seedling Evaluation # of access. Accessions Resistant to Species TTKSK TRTTF TTTTF 3 Races 10 Races Wild emmer 880 152 178 123 32 11 Persian wheat 77 33 12 19 15 12 Polish wheat 66 15 14 13 11 10 Oriental wheat 66 6 1 0 0 0 Poulard wheat 414 44 114 146 43 42 TOTAL 1503 250 (16.3%) 319 (21.2%) 301 (20.0%) 101 (6.7%) 75 (5.0%) 17
  18. 18. Infection Types at Seedling Stage Wild emmer wheat (T. turgidum ssp. dicoccoides) Persian wheat (T. turgidum ssp. carthlicum) 18
  19. 19. Genetics of Resistance and Mapping 45 biparental crosses 27 durum, 5 emmer, 6 wild emmer, 2 Persian, 2 Polish, 3 Poulard 19 F3 generation Phenotypic evaluation at seedling (TTKSK TRTTF) Bulk Segregant Analysis 90K SNP platform Identify chromosomal region of interest Genotype F2 population with SNPs markers Resistant in all seedling evaluations F6 generation Field evaluation in Ethiopia and St. Paul QTL mapping 90K SNP platform Susceptible in all seedling evaluations Markers to confirm presence/absence of Sr2
  20. 20. Crosses – Durum (F3 generation) Line Type Origin Resistant genes TTKSK TRTTF CItr 13338 Breed. line Canada 3 recessive 2 dominant PI 520569 Breed. line Chile 1 dominant 3 dominant CItr 17337 Cultivar Canada 1 dominant 1 dominant PI 428549 Cultivar France 1 dominant 2 dominant PI 506469 Cultivar Colorado (USA) 1 dominant 3 dominant PI 191645 Old cultivar Brazil 1 dominant 1 dominant PI 298547 Landrace Ethiopia 2 dominant 2 dominant PI 479923 Landrace Ethiopia 2 recessive 2 recessive PI 479959 Landrace Ethiopia 1 dominant 1 dominant PI 519559 Landrace Syria 1 dominant 1 dominant 20
  21. 21. Crosses – Other Tetraploids Species Resistant Line TTKSK TRTTF TTTTF Emmer PI 101971 1 part. dominant 1 part. dominant 2 dominant Emmer PI 193883 1 recessive 1 recessive 1 dominant + 1 recessive Emmer PI 217640 1 part. dominant 1 part. dominant 1 dominant + 1 recessive Emmer PI 298582 1 recessive 1 recessive 1 dominant + 1 recessive Emmer PI 319869 1 recessive 1 recessive 1 dominant + 1 recessive Wild emmer PI 428116 1 part. dominant 2 part. dominant Wild emmer PI 466946 2 part. dominant 2 part. dominant Wild emmer PI 466960 2 part. dominant 2 part. dominant Wild emmer PI 466979 1 part. dominant 1 part. dominant Wild emmer PI 471652 1 part. dominant 1 part. dominant Wild emmer PI 471766 2 recessive 1 part. dominant Persian PI 168672 1 dominant 1 dominant Persian PI 387696 2 dominant 1 dominant Polish PI 384339 1 dominant 1 dominant Poulard CItr 7772 1 recessive 1 dominant Poulard CItr 7840 1 recessive 2 dominant Poulard PI 387336 1 recessive 1 dominant 21
  22. 22. 90K SNP Chip Line Line Type Origin Durum PI 298547 Landrace Ethiopia Durum PI 479923 Landrace Ethiopia Durum PI 479959 Landrace Ethiopia Durum PI 519559 Landrace Syria Durum PI 191645 Old cultivar Brazil Durum PI 506469 Cultivar USA Durum PI 428549 Cultivar France Emmer PI 217640 Cultivated India Wild emmer PI 466960 Wild Israel Wild emmer PI 466946 Wild Syria Poulard PI 387336 Cultivated Ethiopia Parents F1 PI 134946 x PI 387336 Parents F1 Citr 7966 x PI 217640 22
  23. 23. Aegilops Species Genome # of accessions Seedling evaluation TTKSK TRTTF TTTTF 3 Races Ae. cylindrica DDCC 151 133 1 102 1 Ae. geniculata MMUU 183 145 159 156 136 Ae. triuncialis UUCC 353 290 198 315 166 Ae. biuncialis UUMM 262 75 179 82 34 Ae. neglecta UUMM 202 189 183 170 158 Ae. peregrina SSUU 73 64 47 24 14 TOTAL 1224 896 (73.2%) 767 (62.7%) 849 (69.3%) 509 (41.6%) Accessions deposited at the NSGC (Aberdeen, ID) 23
  24. 24. Infection Types in Aegilops Ae. biuncialis Ae. cylindrica Ae. neglecta Ae. triuncialis 24
  25. 25. Genetics of Resistance and Mapping ● 25 intraspecific crosses were performed in the six Aegilops species ● Objectives: 1. to elucidate the genetics of stem rust resistance in Aegilops spp. 2. to develop genetic linkage maps for each species and map stem rust resistance genes 25 Species Accession Origin Infection Type Gene/s Ae. peregrina PI 604185 South Israel 2 1 part. dominant Ae. peregrina PI 604193 North Israel ; 1 dominant Ae. triuncialis PI 254861 Iraq 2- 2 dominant Ae. triuncialis PI 221899 Afghanistan 22- 2 dominant Ae. triuncialis PI 374357 Serbia ; 1 dominant
  26. 26. Summary ● Races identified in Ethiopia are virulent on genes effective against Ug99 (Sr13, Sr36, Tmp), and genes widely used in durum breeding programs (Sr13, Sr9e) ● Cultivated and wild tetraploids are a good source of resistance genes and could be used in wheat improvement for stem rust resistance 26
  27. 27. Acknowledgements ● USDA-ARS, Cereal Disease Laboratory stem rust group ● Scientists and Staff at EIAR, Ethiopia (Debre Zeit R.C.) ● H. Bockelman, USDA-ARS National Small Grains Collection ● S. Chao, USDA-ARS Red River Valley Agricultural Research Center ● Durable Rust Resistance of Wheat (DRRW), Cornell University 27

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