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Title: Development and validation of a breeder-friendly KASPar marker for wheat leaf rust resistance locus Lr21

item NEELAM, KUMARI - North Carolina State University
item Brown-Guedira, Gina
item HUANG, LI - Montana State University

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2012
Publication Date: 5/1/2013
Citation: Neelam, K., Brown Guedira, G.L., Huang, L. 2013. Development and validation of a breeder-friendly KASPar marker for wheat leaf rust resistance locus Lr21. Molecular Breeding. 31:233-237.

Interpretive Summary: Leaf rust is one of the major fungal diseases of wheat worldwide. The wheat leaf rust resistance gene Lr21 has been transferred to cultivated wheat from the wild goatgrass species Aegilops tauschii. This gene is an important source of resistance in North American hard red spring wheat cultivars that account for approximately 50% of the spring wheat acreage in the Northern Great Plains. By cloning and sequencing the susceptible versions of the gene from diverse wheat lines, we were able to develop an easily assayed DNA marker specific to the resistance gene. When this marker was evaluated on 384 US wheat lines, including winter wheat lines adapted to the eastern growing region of the U.S., it was found to be 100% effective in differentiating resistant and susceptible wheat lines.

Technical Abstract: Development and utilization of genetic markers play a pivotal role in marker assisted breeding of wheat cultivars with pyramids of disease resistance genes. The objective of this study is to develop a closed tube, gel-free assay for high throughput genotyping of leaf rust resistance locus Lr21. Polymorphism identified from re-sequencing of a 2.4 kb fragment covering the functional region of the Lr21 gene from the second to the fourth indels was targeted for assay development. The generated sequence data revealed the 88 or 105 bp indel in the first intron of the Lr21 gene in the selected resistant cultivars as compared to susceptible U.S. spring and winter wheat cultivars. Allele specific primers for a KASPar assay were designed around the junction of the indel at position 1346 bp. The marker was tested on a panel of 384 US wheat lines and found to be effective in differentiating resistant and susceptible genotypes.