Genetic map of stem rust resistant gene Sr35 in T. monococcum

W. Zhang


Department of Plant Sciences, University of California-Davis, USA

M. Rouse, Z. Abate, Y. Jin, and J. Dubcovsky



With the TTKS family of races virulent on most genes currently providing protection against stem rust worldwide, identifying, mapping, and deploying resistance genes effective against these races has become critical.  We present here a genetic map of Sr35.  Both parents of our diploid mapping population (DV92/G3116, 142 SSD lines) are resistant to TTKSK, but the population segregates for resistance to TRTTF (Yemen) and RKQQC (US). Race analysis suggests that G3116 carries Sr21 and DV92 both Sr21 and Sr35.  Resistance to TRTTF and RKQQC was mapped to a 6 cM interval on chromosome 3AmL between markers BF483299 and CJ656351.  This interval corresponds to a 178-kb region in Brachypodium which contains only 16 annotated genes and exhibits a small inversion (including 2 genes) and a putative insertion (2 genes) relative to rice and sorghum.  This map contains closely-linked markers to Sr35 and provides the initial step for this gene's positional cloning.