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.
- MeSH
- Basidiomycota patogenita MeSH
- chromozomy rostlin genetika MeSH
- duplikace genu MeSH
- exprese genu MeSH
- fenotyp MeSH
- imunita rostlin genetika MeSH
- lipnicovité klasifikace genetika MeSH
- mapování chromozomů MeSH
- mediátorový komplex genetika MeSH
- mutace MeSH
- nemoci rostlin genetika imunologie mikrobiologie MeSH
- odolnost vůči nemocem genetika MeSH
- pšenice genetika imunologie mikrobiologie MeSH
- regulace genové exprese u rostlin MeSH
- rostlinné geny genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
KEY MESSAGE: Lr76 and Yr70 have been fine mapped using the sequence of flow-sorted recombinant 5D chromosome from wheat-Ae. umbellulata introgression line. The alien introgression has been delineated to 9.47-Mb region on short arm of wheat chromosome 5D. Leaf rust and stripe rust are among the most damaging diseases of wheat worldwide. Wheat cultivation based on limited number of rust resistance genes deployed over vast areas expedites the emergence of new pathotypes warranting a continuous deployment of new resistance genes. In this paper, fine mapping of Aegilops umbellulata-derived leaf rust and stripe rust resistance genes Lr76 and Yr70 is being reported. We flow sorted and paired-end sequenced 5U chromosome of Ae. umbellulata, recombinant chromosome 5D (5DIL) from wheat-Ae. umbellulata introgression line pau16057 and 5DRP of recurrent parent WL711. Chromosome 5U reads were mapped against the reference Chinese Spring chromosome 5D sequence, and alien-specific SNPs were identified. Chromosome 5DIL and 5DRP sequences were de novo assembled, and alien introgression-specific markers were designed by selecting 5U- and 5D-specific SNPs. Overall, 27 KASP markers were mapped in high-resolution population consisting of 1404 F5 RILs. The mapping population segregated for single gene each for leaf rust and stripe rust resistance. The physical order of the SNPs in pau16057 was defined by projecting the 27 SNPs against the IWGSC RefSeq v1.0 sequence. Based on this physical map, the size of Ae. umbellulata introgression was determined to be 9.47 Mb on the distal most end of the short arm of chromosome 5D. This non-recombining alien segment carries six NB-LRR encoding genes based on NLR annotation of assembled chromosome 5DIL sequence and IWGSC RefSeq v1.1 gene models. The presence of SNPs and other sequence variations in these genes between pau16057 and WL711 suggested that they are candidates for Lr76 and Yr70.
- MeSH
- Aegilops genetika MeSH
- Basidiomycota růst a vývoj patogenita MeSH
- chromozomy rostlin MeSH
- fenotyp MeSH
- genetické markery MeSH
- genová introgrese MeSH
- jednonukleotidový polymorfismus MeSH
- listy rostlin genetika mikrobiologie MeSH
- mapování chromozomů MeSH
- nemoci rostlin genetika mikrobiologie MeSH
- odolnost vůči nemocem genetika MeSH
- pšenice genetika mikrobiologie MeSH
- rekombinace genetická MeSH
- rostlinné geny MeSH
- šlechtění rostlin MeSH
- telomery genetika MeSH
- vysoce účinné nukleotidové sekvenování MeSH
- Publikační typ
- časopisecké články MeSH
