Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/15/2004
Publication Date: 1/15/2005
Citation: Mateos-Hernandez, M., Singh, R.P., Hulbert, S., Gill, B.S., Brown Guedira, G.L. 2004. Targeted mapping of wheat ests linked to the adult plant resistance gene lr46 using synteny with rice. Plant and Animal Genome Abstracts.
Technical Abstract: Leaf rust or brown rust (caused by Puccinia triticina) is a widespread fungal disease in wheat growing regions. Breeding for resistant cultivars is the most feasible alternative to control the disease. Two adult plant resistance genes (Lr34 and Lr46) have been reported to confer stable resistance to all known races of the pathogen and are thought to be durable. The Lr46 gene is located in the terminal region of wheat chromosome 1BL. Our objective was to exploit the syntenic relationship between the distal part of chromosome 1BL of wheat and 5L of rice to saturate the Lr46 region and develop markers tightly linked to the gene. Wheat expressed sequence tags (ESTs) that mapped in the FL=0.85-0.89 by the NSF project were blasted against the rice genome sequence and wheat ESTs with significant homology to sequences from 5L of rice were chosen for STS primer design. The STS markers were physically mapped using wheat aneuploids and deletion lines from chromosome 1BL and genetically mapped in two populations segregating for Lr46. A total of 21 STS markers physically mapped in the chromosomal region of Lr46, allowing us to determine the physical location of the gene. Eight polymorphic STS markers were genetically mapped in the Lr46 region. The most closely linked STS markers flanking Lr46 were located 3.0 cM proximal and 0.7 cM distal to the gene. These STS markers can be used to design markers for MAS and will facilitate positional cloning of the gene.