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United States Department of Agriculture

Agricultural Research Service

Title: Characterization and mapping of cryptic alien introgression from Aegilops geniculata with new leaf rust and stripe rust resistance genes Lr57 and Yr40 in wheat.

Authors
item Kuraparthy, Vasu - KANSAS STATE UNIVERSITY
item Chhuneja, Parveen - PUNJAB AGRI UNIVERSITY
item Dhaliwal, Harcharan - PUNJAB AGRI UNIVERSITY
item Kaur, Satinder - PUNJAB AGRI UNIVERSITY
item Bowden, Robert
item Gill, Bikram - KANSAS STATE UNIVERSITY

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 5, 2007
Publication Date: March 14, 2007
Citation: Kuraparthy, V., Chhuneja, P., Dhaliwal, H., Kaur, S., Bowden, R.L., Gill, B. 2007. Characterization and mapping of cryptic alien introgression from Aegilops geniculata with new leaf rust and stripe rust resistance genes Lr57 and Yr40 in wheat.. Theoretical and Applied Genetics.114:1379-1389.

Interpretive Summary: Leaf rust and stripe rust are important foliar diseases of wheat worldwide. Leaf rust and stripe rust resistant introgression lines were developed by crossing common wheat with the wild wheat relative, Aegilops geniculata. Introgression lines showed similar and complete resistance to the most prevalent pathotypes of leaf rust and stripe rust in Kansas (USA) and Punjab (India). Some alien introgression lines had very small translocation segments that were not visible by microscopic examination. These cryptic alien introgression lines contained new resistance genes for leaf rust and stripe rust that were designated Lr57 and Yr40, respectively. This is the first documentation of a successful transfer and characterization of cryptic alien introgression from Ae. geniculata conferring resistance to both leaf rust and stripe rust in wheat.

Technical Abstract: Leaf rust and stripe rust are important foliar diseases of wheat worldwide. Leaf rust and stripe rust resistant introgression lines were developed by induced homoeologous chromosome pairing between wheat chromosome 5D and 5Mg of Aegilops geniculata (UgMg). Characterization of rust resistant BC2F5 and BC3F6 homozygous progenies using genomic in situ hybridization with Aegilops comosa (M) DNA as probe identified three different types of introgressions; two cytologically visible and one invisible (termed cryptic alien introgression). All three types of introgression lines showed similar and complete resistance to the most prevalent pathotypes of leaf rust and stripe rust in Kansas (USA) and Punjab (India). Diagnostic polymorphisms between the alien segment and recipient parent were identified using physically mapped RFLP probes. Molecular mapping revealed that cryptic alien introgression conferring resistance to leaf rust and stripe rust comprised less than 5% of the 5DS arm and was designated T5DL-5DS-5MgS(0.95). Genetic mapping with an F2 population of Wichita x T5DL-5DS-5MgS(0.95) demonstrated the monogenic and dominant inheritance of resistance to both diseases. Two diagnostic RFLP markers, previously mapped on chromosome arm 5DS, co-segregated with the rust resistance in the F2 population. The unique map location of the resistant introgression on chromosome T5DL-5DS-5MgS(0.95) suggested that the leaf rust and stripe rust resistance genes were new and were designated Lr57 and Yr40. This is the first documentation of a successful transfer and characterization of cryptic alien introgression from Ae. geniculata conferring resistance to both leaf rust and stripe rust in wheat.

Last Modified: 10/1/2014
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