Major Gene for Field Stem Rust Resistance Co-Locates with Resistance Gene Sr12 in 'Thatcher' Wheat.
Stem rust, caused by Puccinia graminis (Pgt), is a damaging disease of wheat that can be controlled by utilizing effective stem rust resistance genes. 'Thatcher' wheat carries complex resistance to stem rust that is enhanced in the presence of the resistance gene Lr34. The purpose of this study was to examine APR in 'Thatcher' and look for genetic interactions with Lr34. A RIL population was tested for stem rust resistance in field nurseries in Canada, USA, and Kenya. BSA was used to find SNP markers associated with reduced stem rust severity. A major QTL was identified on chromosome 3BL near the centromere in all environments. Seedling testing showed that Sr12 mapped to the same region as the QTL for APR. The SNP markers were physically mapped and the region carrying the resistance was searched for sequences with homology to members of the NB-LRR resistance gene family. SNP marker from one NB-LRR-like sequence, NB-LRR3 co-segregated with Sr12. Two additional populations, including one that lacked Lr34, were tested in field nurseries. NB-LRR3 mapped near the maximum LOD for reduction in stem rust severity in both populations. Lines from a population that segregated for Sr12 and Lr34 were tested for seedling Pgt biomass and infection type, as well as APR to field stem rust which showed an interaction between the genes. We concluded that Sr12, or a gene closely linked to Sr12, was responsible for 'Thatcher'-derived APR in several environments and this resistance was enhanced in the presence of Lr34.
Agriculture and Agri-Food Canada, Cereal Research Centre, Morden, Manitoba, Canada.
Colin W
CW
Hiebert
Department of Plant Pathology, University of Minnesota, Saint Paul, Minnesota, United States of America.|United States Department of Agriculture-Agriculture Research Service, Cereal Disease Laboratory, Saint Paul, Minnesota, United States of America.
James A
JA
Kolmer
Agriculture and Agri-Food Canada, Cereal Research Centre, Morden, Manitoba, Canada.
Curt A
CA
McCartney
Department of Plant Pathology, University of Minnesota, Saint Paul, Minnesota, United States of America.
Jordan
J
Briggs
Agriculture and Agri-Food Canada, Brandon Research Centre, Brandon, Manitoba, Canada.
Tom
T
Fetch
Plant Breeding Institute, University of Sydney, Cobbitty, New South Wales, Australia.
Harbans
H
Bariana
INRA UMR1095 Genetics, Diversity and Ecophysiology of Cereals, Clermont-Ferrand, France.
Frederic
F
Choulet
Department of Plant Pathology, University of Minnesota, Saint Paul, Minnesota, United States of America.|United States Department of Agriculture-Agriculture Research Service, Cereal Disease Laboratory, Saint Paul, Minnesota, United States of America.
Matthew N
MN
Rouse
Commonwealth Scientific and Industrial Research Organisation-Agriculture and Food, Canberra, Australian Capital Territory, Australia.
Wolfgang
W
Spielmeyer
D001487:Basidiomycota / Q000472:pathogenicity; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D060467:Disease Resistance / Q000235:genetics*; D004843:Epistasis, Genetic; D005838:Genotype; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D018547:Plant Stems / Q000254:growth & development / Q000382:microbiology; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci / Q000235:genetics*; D036226:Seedlings / Q000235:genetics / Q000254:growth & development; D014908:Triticum / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology