Soybean gene for resistance to Aphis glycines
Inventors
Hill, Curtis B. • Hartman, Glen L.
Assignees
US Department of Agriculture USDA • University of Illinois System
Publication Number
US-7928286-B2
Publication Date
2011-04-19
Expiration Date
2027-10-09
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Abstract
An Aphis glycines resistance Rag2 gene is provided herein, along with methods for identifying its presence using marker-assisted selection. A cultivar of G. max having resistance to Aphis glycines conferred by the Rag2 gene has been identified. The Rag2 gene, as well as the methods, aphid-resistant varieties, and markers disclosed herein may be used to breed new elite lines expressing soybean aphid resistance.
Core Innovation
An Aphis glycines resistance Rag2 gene is provided, along with methods for identifying its presence using marker-assisted selection. A cultivar of Glycine max having resistance to Aphis glycines conferred by the Rag2 gene has been identified. The Rag2 gene, along with methods, aphid-resistant varieties, and markers disclosed, may be used to breed new elite lines expressing soybean aphid resistance.
The Rag2 gene is non-allelic with the previously discovered Rag1 gene and conditions strong resistance to the soybean aphid by preventing aphid colonization through reduced aphid multiplication, survival, lifespan, and nymph development. This resistance is dominant in heterozygous plants and effective against all known soybean aphid biotypes. The gene is mapped to linkage group F and is closely flanked by SSR markers Soyhsp176 and Satt510, enabling efficient identification through marker-assisted selection without live aphid inoculation.
The invention addresses the need for efficient and cost-effective molecular tools to enable breeding of Aphis glycines resistance into high-yielding Glycine max soybean varieties. Prior control measures lacked an integrated management approach and molecular tools for high-throughput screening for resistance were lacking. The presence of molecular markers tightly linked to Rag2 facilitates marker-assisted selection to expedite development of aphid-resistant soybean cultivars by introgression of Rag2 into adapted cultivars, alone or combined with other aphid resistance genes such as Rag1.
Claims Coverage
The patent includes three independent claims covering methods for detecting and determining the presence of the Rag2 resistance gene in soybean germplasm by marker-assisted selection, including hybridization to linked molecular markers and PCR fragment size comparison.
Method for detecting Rag2 resistance locus by marker-assisted selection
A method for determining the presence or absence of the Rag2 gene for resistance to Aphis glycines in soybean germplasm by analyzing allelic polymorphisms of markers Soyhsp176 and Satt510 flanking the Rag2 locus on linkage group F, involving PCR amplification and size comparison of polymorphic marker fragments to those from a resistant reference variety PI200538.
Use of nucleic acid hybridization to markers linked to Rag2 locus
The method further comprises hybridizing soybean genomic DNA to nucleic acid fragments or primers of DNA markers mapping within 20 cM of Soyhsp176 and/or Satt510 that show allelic polymorphism linked to Rag2, enabling detection of the resistance locus.
Hybridization using specific polymorphic markers
The method uses specific polymorphic markers selected from the group consisting of Sat—234, Soyhsp176, Sat—297, and Satt510 for hybridization to detect Rag2 presence.
Use of multiple polymorphic markers for detection
The method involves hybridizing at least two polymorphic markers to genomic DNA of soybean linkage group F germplasm to improve accuracy of Rag2 locus detection.
The independent claims cover molecular marker-based methods for identifying the Rag2 aphid resistance gene locus in soybean germplasm, centered on polymorphic SSR markers closely linked to Rag2 on linkage group F, enabling efficient marker-assisted selection.
Stated Advantages
Facilitates efficient and cost-effective identification of aphid-resistant soybean plants without requiring live aphid inoculation.
Expedites breeding of new soybean cultivars resistant to soybean aphid by marker-assisted selection.
Enables stacking of multiple aphid resistance genes to increase durability and effectiveness of resistance.
Provides molecular markers tightly linked to resistance gene, improving screening accuracy.
Documented Applications
Breeding and selection of soybean germplasm with resistance to soybean aphid Aphis glycines using marker-assisted selection for the Rag2 gene based on SSR markers Soyhsp176 and Satt510.
Introgression of the Rag2 gene into susceptible or less resistant soybean cultivars for development of adapted aphid-resistant cultivars.
Stacking of Rag2 resistance from linkage group F with Rag1 and related resistance genes from linkage group M to develop soybean cultivars with enhanced resistance.
Use of molecular markers for rapid screening of breeding populations and progeny for presence of Rag2 resistance locus.
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