Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2005
Publication Date: 3/1/2006
Citation: Miklas, P.N., Hu, J., Grunwald, N.J., Larsen, K.M. 2006. Potential application of TRAP (Targeted Region Amplified Polymorphism) markers for mapping and tagging disease resistance traits in common bean. Crop Science. 46:910-916. Interpretive Summary: A new marker system Targeted Region Amplified Polymorphism (TRAP) developed by USDA-ARS (J. Hu; Fargo, ND) in sunflower was applied to tagging and mapping disease resistance traits in common bean. Resistance genes often provide the most effective and economical means for control of pathogen-induced diseases in bean. DNA markers linked with the R genes can be used to select for resistance without the pathogen. This marker-assisted selection facilitates breeding for disease resistance in bean and other crops. TRAP markers were found to be effective in tagging disease resistance genes in bean. The TRAP system will provide an additional marker tool for genomic applications in disease resistance breeding in bean.
Technical Abstract: Genetic resistance is an important component of integrated strategies used to control problematic diseases in common bean (Phaseolus vulgaris L.). Molecular linkage maps have been used to identify, tag, and map disease resistance genes and QTL in common bean, leading to improved breeding strategies and implementation of marker-assisted selection. Most widely used marker types, RAPD and AFLP, for linkage mapping in bean are located randomly throughout the genome, and associate with particular traits by chance. We sought to determine potential application of a new marker system, TRAP, which uses expressed sequence information and a bioinformatics approach to generate polymorphic markers around targeted candidate gene sequences. TRAP markers were amplified by fixed primers designed against sequenced EST associated with disease resistance in the Compositae Genomics database or against sequenced RGA from common bean. Seventeen of 85 TRAP markers located in the BAT 93/Jalo EEP558 core mapping population mapped in the vicinity of R genes. Six of 21 TRAP markers generated in the Dorado/XAN 176 mapping population were linked with newly identified QTL, two conditioning resistance to ashy stem blight (14% and 16% of the phenotypic variation explained, R2), and one each conferring resistance to BGYMV (15%) and common bacterial blight (30%). The TRAP marker system has potential for mapping regions of the common bean genome linked with disease resistance.