Soybean genes for resistance to Aphis glycines
Inventors
Hill, Curtis B. • Hartman, Glen L. • Li, Yan • Diers, Brian • Carlson, Shawn
Assignees
US Department of Agriculture USDA • University of Illinois System
Publication Number
US-7994389-B2
Publication Date
2011-08-09
Expiration Date
2025-06-21
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Abstract
Aphis glycines resistance (RAG) genes are provided by this invention, along with methods for identifying their presence using marker-assisted selection. Varieties of G. max and G. soja having resistance to A. glycines have been identified. The RAG genes, 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
This invention provides soybean genes conferring resistance to the soybean aphid, Aphis glycines, termed RAG genes, along with methods for identifying their presence using marker-assisted selection. The identified RAG genes map to specific regions on soybean linkage group M and are found in varieties of Glycine max and Glycine soja that exhibit aphid resistance. The invention also includes methods for breeding new elite soybean lines expressing this resistance trait using these genes and associated molecular markers.
The problem addressed is the damage caused by the soybean aphid, an invasive pest in North America since 2000, which causes significant yield losses, plant stunting, leaf distortion, and reduced pod set. Because this aphid can rapidly spread and also transmit several viruses harmful to soybean crops, there is a need for effective aphid control. Current integrated pest management strategies lack a component of genetic plant resistance, especially in cultivated Glycine max, where no aphid resistance had previously been reported. Thus, there is a need for molecular tools and methods for breeding aphid-resistant soybean varieties to reduce input costs and improve crop yields.
The invention includes a novel method of detecting the presence of aphid resistance genes by screening for molecular markers closely linked to the RAG locus on soybean linkage group M, particularly markers Satt435 and Satt463. These markers flank the locus containing the Rag1 gene. The linkage between resistance and these markers enables reliable marker-assisted selection to introgress aphid resistance into susceptible soybean germplasm. The invention also covers soybean plants, seeds, and tissue cultures possessing the RAG gene produced by marker-assisted breeding methods.
Claims Coverage
The patent contains one independent claim defining a method for identifying aphid resistance genes in soybean germplasm using molecular markers.
Method for identifying soybean aphid resistance gene by marker-assisted selection
A method to detect the presence or absence of a gene coding for resistance to Aphis glycines in soybean germplasm by analyzing the germplasm through marker-assisted selection (MAS). This involves detecting a RAG locus on soybean linkage group M flanked by SSR markers Satt435 and Satt463, which show allelic polymorphism between resistant and susceptible genotypes and are linked to the resistant gene. The method includes comparing PCR-amplified polymorphic marker fragments from test germplasm to those from resistant varieties Dowling and Jackson to determine gene presence based on fragment size similarity.
Hybridization with nucleic acid fragments corresponding to markers near resistance locus
Methods including hybridizing nucleic acid fragments that comprise sequences of DNA markers mapping within 10 to 20 cM of Satt435 and/or Satt463 SSR markers on linkage group M to the DNA of soybean germplasm to detect presence of resistance genes.
Use of multiple flanking markers for detecting resistance locus
Using at least two DNA marker sequences that flank the RAG locus on opposite sides within about 10 to 20 cM of Satt435 and/or Satt463 SSR markers in hybridization steps to reliably identify the RAG locus in soybean germplasm.
Application of various marker types linked to resistance gene
Employing SSR, RFLP, SNP, and RAPD markers that map within 20 cM of the flanking markers for detecting the gene coding for Aphis glycines resistance by hybridization to soybean germplasm DNA.
The claims cover a marker-assisted selection method for identifying soybean aphid resistance genes based on molecular markers flanking the RAG locus on linkage group M, including using PCR and hybridization techniques with various types of markers closely linked to the resistance gene.
Stated Advantages
Enables reliable and predictable identification of soybean aphid resistance genes using molecular markers.
Facilitates breeding of aphid-resistant soybean varieties through marker-assisted selection, accelerating introgression of resistance traits into elite germplasm.
Reduces input costs for producers by incorporating genetic resistance into soybean crops, which is an ideal method of insect control.
Documented Applications
Breeding of new elite soybean lines expressing resistance to Aphis glycines by introgressing RAG genes into susceptible varieties.
Screening and selection of soybean germplasm for aphid resistance using marker-assisted selection methods based on linkage group M molecular markers.
Producing diagnostic tests for detecting aphid resistance genes in soybean tissue or seeds via PCR and nucleic acid hybridization.
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