Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: December 9, 2009
Publication Date: January 9, 2010
Citation: Azhaguvel, P., Weng, Y., Ma, Y., Luo, M., Simkova, H., Dolezel, J., Rudd, J. 2010. A Candidate Gene for Aphid Resistance in Wheat [abstract]. Plant and Animal Genome Conference. p. 296.
The greenbug, Schizaphis graminum (Rondani), is an important aphid pest of small grain crops in many parts of the world. A single dominant gene, Gb3 originated from Aegilops tauschii has shown consistent and durable resistance against prevailing greenbug biotypes in wheat fields. Previously, we mapped Gb3 in a recombination-rich, telomeric bin of wheat chromosome arm 7DL. High–resolution, sub-genome mapping was carried out using an F2:3 segregating population of Ae. tauschii and two hexaploid wheat populations. Molecular markers were developed by exploring Triticeae ESTs and the syntenic relationships among wheat, rice and Brachypodium distachyon in the Gb3 region. The Brachypodium sequences of chromosome Bd1 aligned with Triticeae ESTs were thoroughly examined. High-degree colinearity between wheat 7DL distal bin and Bd1 was observed. Over 100 7DL-specific molecular markers were fine mapped in the region harboring Gb3. Markers closely linked with Gb3 were used to screen Ae. tauschii and wheat 7DL–specific BAC libraries. BAC contigs were constructed with markers flanking Gb3. Two 7DL BAC clones were fully sequenced; the sequence annotation of BACs (~350 kb) identified a tentative candidate gene for Gb3 which encodes a NB-ARC-LRR domain. Though the functional verification of this candidate gene has been initiated, further screenings of the BAC libraries are underway to complete the contig construction.