Molecular and cytogenetic characterization of a du

Authors: Justin D Faris Steven S Xu Xiwen Cai Timothy L Friesen Yue Jin

Publish Date: 2008/10/17

Volume: 16, Issue: 8, Pages: 1097-1105

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Abstract

Stem rust is a serious disease of wheat that has caused historical epidemics but it has not been a threat in recent decades in North America owing to the eradication of the alternative host and deployment of resistant cultivars However the recent emergence of Ug99 or race TTKS poses a threat to global wheat production because most currently grown wheat varieties are susceptible In this study we evaluated a durum wheat–Aegilops speltoides chromosome translocation line DAS15 for reaction to Ug99 and six other races of stem rust and used molecular and cytogenetic tools to characterize the translocation DAS15 was resistant to all seven races of stem rust Two durum–Ae speltoides translocated chromosomes were detected in DAS15 One translocation involved the short arm centromere and a major portion of the long arm of Ae speltoides chromosome 2S and a small terminal segment from durum chromosome arm 2BL Thus this translocated chromosome is designated T2BL2SL•2SS Cytogenetic mapping assigned the resistance genes in DAS15 to the Ae speltoides segment in T2BL2SL•2SS The Ae speltoides segment in the other translocated chromosome did not harbour stem rust resistance A comparison of DAS15 and the wheat stocks carrying the Ae speltoidesderived resistance genes Sr32 and Sr39 indicated that stem rust resistance gene present in DAS15 is likely novel and will be useful for developing germplasm with resistance to Ug99 Efforts to reduce Ae speltoides chromatin in T2BL2SL•2SS are currently in progress

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