Stem rust resistance in wheat is suppressed by a subunit of the mediator complex
- Hiebert, Colin W.
- Moscou, Matthew J.
- Hewitt, Tim
- Steuernagel, Burkhard
- Hernández-Pinzón, Inma
- Green, Phon
- Pujol, Vincent
- Zhang, Peng
- Rouse, Matthew N.
- Jin, Yue
- McIntosh, Robert A.
- Upadhyaya, Narayana
- Zhang, Jianping
- Bhavani, Sridhar
- Vrana, Jan
- Karafiatova, Miroslava
- Huang, Li [ Montana State University: Plant Sciences & Plant Pathology ]
- Fetch, Tom
- Doležel, Jaroslav
- Wulff, Brande B. H.
- Lagudah, Evans
- Spielmeyer, Wolfgang
Stem rust is an important disease of wheat that can be controlled using resistance genes. The gene SuSr-D1 identified in cultivar ‘Canthatch’ suppresses stem rust resistance. SuSr-D1 mutants are resistant to several races of stem rust that are virulent on wild-type plants. Here we identify SuSr-D1 by sequencing flow-sorted chromosomes, mutagenesis, and map-based cloning. The gene encodes Med15, a subunit of the Mediator Complex, a conserved protein complex in eukaryotes that regulates expression of protein-coding genes. Nonsense mutations in Med15b.D result in expression of stem rust resistance. Time-course RNAseq analysis show a significant reduction or complete loss of differential gene expression at 24 h post inoculation in med15b.D mutants, suggesting that transcriptional reprogramming at this time point is not required for immunity to stem rust. Suppression is a common phenomenon and this study provides novel insight into suppression of rust resistance in wheat.