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Mike Pumphrey, Washington State University
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Stocking the Breeder’s Toolbox:An update on the status of Ug99 resistance
Mike PumphreySept 2, [email protected]
DRRW Pre-breeding efforts:
CIMMYT Cornell Univ. CSIROEIARICCI-Tel Aviv Univ.Kansas State Univ.Univ. of AdelaideUC-DavisUniv. of the Free StateUniv. of MinnesotaUniv. of SydneyUSDA-ARSWashington State Univ.
Why do we need a better toolbox?
Speed and support replacement of rust susceptible varieties with varieties based on complex resistance - globally
Increase diversity of resistance and promote durable resistance
Enable stewardship of resistance sources in a manner never before possible
What tools are needed?
A well-surveyed resistance gene landscape
Additional, useful, sources of resistance
Effective gene pyramids
DNA markers and supporting information
for robust selection/diagnostics
Good germplasm
Deploying COMPLEX resistance
Adult plant/Slow-rusting 3 or more
effective APR genes combined
Seedling/All-stage 3 or more
effective R genes combined
COMPLEX resistance
Susceptible
1 to 2 APR genesor 1+ race-specific gene
2 to 3 APR genesor 1+ race-specific gene
4 to 5 APR genesor 1+ race-specific gene
% Rust Severity
Day of Epidemic
100
80
60
40
20
00 10 20 30 40 503+
This is the goal!
Ug99-family Resistance Loci (circa 2008)
1A 2A 3A 4A 5A 6A 7A
1B 2B 3B 4B 5B 6B 7B
1D 2D 3D 4D 5D 6D 7D
Sr28
Sr13Sr22
Sr40Sr39
Sr33Sr45
Sr35
Sr2
Sr21
Sr25
Sr26
Sr27
Sr29
Sr37
Sr42
Alien introgression with linkage drag
Sr32
Sr1A.1R
Sr50Sr44
Sr43
Red genes are translocations or show reduced recombinationGreen genes are APR lociBlack genes have normal recombination
Ug99-family Resistance Loci (2012)
1A 2A 3A 4A 5A 6A 7A
1B 2B 3B 4B 5B 6B 7B
1D 2D 3D 4D 5D 6D 7D
Sr28
Sr13Sr22
Sr40Sr39
Sr33Sr45
Sr35
Sr2
Sr21
Sr25
Sr26
Sr27
Sr29
Sr37
Sr42Sr32
Sr1A.1R
Sr50Sr44
Sr43
SrTm4
Lr46
SrWeb/Gabo 56
Red genes are translocations or show reduced recombinationGreen genes are APR lociBlack genes have normal recombination
Sr47
Sr51
Sr12
SrND643
Sr55
Sr56
Sr53
Sr52Sr15
Sr57Sr46
Sr1662
SrTr129
SrAt6D SrAt7D
SrSha7 SrC
QTL
QTL QTL
QTL
QTL
QTL
QTL
Sources of Ug99 resistanceGene Chrom
.Origin Notes
Sr2 3BS Tetraploid wheat APR
Sr12 3BS Tetraploid wheat Moderate/background eff.
Sr13 6AL Tetraploid wheat
Sr15 7AL Hexaploid wheat Moderate/background eff.
Sr22 7AL Triticum monococcum Diagnostic markers
Sr25 7DL Thinopyrum ponticum Diagnostic markers
Sr26 6AL Thinopyrum ponticum Diagnostic markers
Sr28 2BL Hexaploid wheat Linkage block, diagnostic
Sr32 2DS Aegilops speltoides New recombinants
Sr33 1DS Aegilops tauschii Linkage block, cloned
Sr35 3AL Triticum monococcum Cloned
Sr37 4B Triticum timopheevii New recombinants
Sources of Ug99 resistanceGene Chrom
.Origin Notes
Sr39 2BS Aegilops speltoides New recombinants
Sr40 2BS Triticum timopheevii New recombinants
Sr42 6DS Hexaploid wheat SrCad?, SrNini?
Sr43 7DL Thinopyrum elongatum
New recombinants
Sr44 7DS Th. intermedium New translocation
Sr45 1DS Aegilops tauschii Linkage block
Sr46 2DS Aegilops tauschii
Sr47 2BL Aegilops speltoides New recombinants
Sr50 1DS Rye Linkage block
Sr51 3DS Aegilops searsii Recombinants underway
Sr52 6AL Dasypyrum villosum Temperature sensitive
Sr53 5DL Aegilops geniculata New recombinants
Sources of Ug99 resistanceGene Chrom
.Origin Notes
Sr55 4DL Hexaploid wheat APR-Lr67/Yr46
Sr56 5BL Hexaploid wheat APR
Sr57 7DS Hexaploid wheat APR-Lr34/Yr18, cloned
Lr46 1BL Hexaploid wheat APR-Yr29
Temporary Designations
SrWeb/Gabo56
2BL Hexaploid wheat Linkage block
Sr1662 1DS Aegilops tauschii
SrTr129
6AS
SrTm4 2A Triticum monococcum
SrAt6D 6D Aegilops tauschii
SrAt7D 7D Aegilops tauschii
Sources of Ug99 resistanceGene Chrom
.Origin Notes
Temporary Designations
SrSha7
SrC
SrNini 6DS
SrND643
4AL
Consistent QTL (by association mapping or bi-parental mapping)
1A, 1B, 2B, 3D, 4A, 5B, 6B, 7A, 7B
CIMMYT germplasm via bi-parental and AM approaches
Several additional sources and better tools are coming (from many directions):A few DRRW project examples
Discovery from wheat relatives
Introgression, allelism tests, mapping, chromosome engineering
Aegilops species, wild tetraploids, Dasypyrum villosum
Association mapping
Cytogenetic improvement Thinopyrum
intermedium- Group 2
Marker development
Sequencing, 9000 SNP, 90,000K SNP platforms accelerating progress
Consolidated/standardized/dense
90,000 SNP genotyping ~160 Sr resistance sources from USDA-ARS ~90 Lr resistance sources from USDA-ARS ~400 Yr resistance sources from USDA-ARS
Washington State Numerous populations by 9K or 90K
Map-based cloning (Sr33, Sr35, others)
Linkage Block Development
Recombining linked loci to enhance stewardship and breeding ease
Genomic selection/prediction
So what?
There has never been a more opportune time for the international community to embrace strategic deployment and responsible stewardship of our genetic resources for durable stem rust control …
……before we lose tools that we can’t afford to replace.
AcknowledgementsBMGF/DFIDCornell
UniversityCollaborator
institutionsBGRI IPP-CAAS
