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United States Department of Agriculture

Agricultural Research Service

Research Project: CONTROL OF RUSTS OF CEREAL CROPS

Location: Wheat Genetics, Quality Physiology and Disease Research

Title: Molecular Mapping of a Stripe Rust Resistance Gene in Spring Wheat Cultivar ‘Zak’

Authors
item Sui, X -
item Wang, M -
item CHEN, XIANMING

Submitted to: Journal of Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 18, 2009
Publication Date: September 10, 2009
Repository URL: http://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-99-10-1209
Citation: Sui, X.X., Wang, M.N., Chen, X. 2009. Molecular Mapping of a Stripe Rust Resistance Gene in Spring Wheat Cultivar ‘Zak’. Phytopathology 99:1209-1215.

Interpretive Summary: Stripe rust is one of the most devastating foliar diseases on wheat. Growing resistant cultivars is the best approach for control of the disease. Although the stripe rust resistance in spring wheat cultivar ‘Zak’ has been circumvented by a group of races of the pathogen predominant in the United States since 2000, the resistance gene(s) in Zak were unknown. To identify and map the gene(s) for resistance to stripe rust, Zak was crossed with susceptible wheat genotype ‘Avocet Susceptible’ (AVS). Seedlings of the parents and F1, F2, and F3 progeny were tested with races PST-43 and PST-45 under the controlled greenhouse conditions. Genetic analysis determined that Zak has a single dominant gene, designed as YrZak, conferring race-specific all-stage resistance. Molecular markers linked to the resistance gene were identified and used to map the gene to the long arm of chromosome 2B. The resistance gene in Zak was identified to be different, but closely linked to the Yr5 gene using genetic analysis and molecular markers. The results of race reactions and chromosomal locations indicated that YrZak is different from previously identified genes for resistance to stripe rust.

Technical Abstract: Stripe rust, caused by Puccinia striiformis f. sp. tritici (PST), is one of the most devastating foliar diseases on wheat (Triticum aestivum) worldwide. Growing resistant cultivars is the best approach for control of the disease. Although the stripe rust resistance in spring wheat cultivar ‘Zak’ has been circumvented by a group of races of the pathogen predominant in the United States since 2000, the resistance gene(s) in Zak were unknown. To identify and map the gene(s) for resistance to stripe rust, Zak was crossed with susceptible wheat genotype ‘Avocet Susceptible’ (AVS). Seedlings of the parents and F1, F2, and F3 progeny were tested with races PST-43 and PST-45 under the controlled greenhouse conditions. Genetic analysis determined that Zak has a single dominant gene, designated as YrZak, conferring race-specific all-stage resistance. Resistance gene analog polymorphism (RGAP), simple sequence repeat (SSR), and sequence tagged site (STS) techniques were used to identify molecular markers linked to YrZak. A linkage group of three RGAP, three SSR, and three STS markers was constructed for YrZak using 205 F3 lines. Amplification of a set of nulli-tetrasomic Chinese Spring lines with RGAP marker Xwgp102 indicated that YrZak is present on chromosome 2B. The three SSR markers further mapped YrZak to the long arm of chromosome 2B. Amplification of chromosome 2B deletion lines with SSR marker Xgwm501 further confirmed that YrZak is on chromosome 2BL. To determine the genetic distance between YrZak and Yr5, which also is present on chromosome 2BL, 300 F2 plants from cross Zak/Yr5 were tested with PST-43. Three susceptible plants were identified from the F2 population, indicating that YrZak and Yr5 are closely linked with a genetic distance of 3.4 cM. The results of race reactions and chromosomal locations indicated that YrZak is different from previously identified genes for resistance to stripe rust.

Last Modified: 8/27/2014
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