We report on pyramiding different disease resistance genes against fungal pathogens in Canadian winter wheat germplasm based on available DNA markers and gene sequences.Genetic resistance represents a safe, economical...We report on pyramiding different disease resistance genes against fungal pathogens in Canadian winter wheat germplasm based on available DNA markers and gene sequences.Genetic resistance represents a safe, economical and ecological method for protecting plants, growers and the health of consumers. Major diseases of wheat on the Canadian Prairies are common bunt, rusts(leaf, stem and stripe) and Fusarium head blight. Over the years markers for resistance genes against these diseases have been identified and used by the international wheat community. We describe markers that we have used to pyramid different resistance genes and indicate their presence in Canadian winter wheat cultivars issued from the winter wheat breeding program at the Agriculture and Agri-Food Canada,Lethbridge Research and Development Centre, the only winter wheat breeding program in Western Canada actively delivering new varieties for all regions of the Canadian Prairies.The sources of resistance and identities of PCR primers and amplification conditions are indicated to enable the transfer and pyramiding of different resistance(R) genes to breeding lines. We conclude by reviewing new tools for identifying R genes in wheat and indicate how mutagenesis and gene editing can help future efforts to extend the protection offered by known R genes.展开更多
The first seedling or all-stage resistance （R） R gene against stripe rust isolated from Moro wheat （Triticum aes- tivum L.） using a map-based cloning approach was identified as Yr10. Clone 4B of this gene encodes ...The first seedling or all-stage resistance （R） R gene against stripe rust isolated from Moro wheat （Triticum aes- tivum L.） using a map-based cloning approach was identified as Yr10. Clone 4B of this gene encodes a highly evolutionary- conserved and unique CC-NBS-LRR sequence. Clone 4E, a homolog of Yr10, but lacking transcription start site （TSS） and putative TATA-box and CAAT-box, is likely a non-expressed pseudogene. Clones 4B and 4E are 84% identical and divergent in the intron and the LRR domain. Gene silencing and transgenesis were used in conjunction with inoculation with differen- tially avirulent and virulent stripe rust strains to demonstrate Yr10 functionality. The Yr10 CC-NBS-LRR sequence is unique among known CC-NBS-LRR R genes in wheat but highly conserved homologs （E = 0.0） were identified in Aegilops tauschii and other monocots including Hordeum vulgare and Brachypodium distachyon. Related sequences were also identified in genomic databases of maize, rice, and in sorghum. This is the first report of a CC-NBS-LRR resistance gene in plants with limited homologies in its native host, but with numerous homologous R genes in related monocots that are either host or non-hosts for stripe rust. These results represent a unique example of gene evolution and dispersion across species.展开更多
基金Funding from the Agriculture and Agri-Food Canada Peer Review and Growing Forward programs,and Ducks Unlimited Canada is greatly appreciated
文摘We report on pyramiding different disease resistance genes against fungal pathogens in Canadian winter wheat germplasm based on available DNA markers and gene sequences.Genetic resistance represents a safe, economical and ecological method for protecting plants, growers and the health of consumers. Major diseases of wheat on the Canadian Prairies are common bunt, rusts(leaf, stem and stripe) and Fusarium head blight. Over the years markers for resistance genes against these diseases have been identified and used by the international wheat community. We describe markers that we have used to pyramid different resistance genes and indicate their presence in Canadian winter wheat cultivars issued from the winter wheat breeding program at the Agriculture and Agri-Food Canada,Lethbridge Research and Development Centre, the only winter wheat breeding program in Western Canada actively delivering new varieties for all regions of the Canadian Prairies.The sources of resistance and identities of PCR primers and amplification conditions are indicated to enable the transfer and pyramiding of different resistance(R) genes to breeding lines. We conclude by reviewing new tools for identifying R genes in wheat and indicate how mutagenesis and gene editing can help future efforts to extend the protection offered by known R genes.
文摘The first seedling or all-stage resistance （R） R gene against stripe rust isolated from Moro wheat （Triticum aes- tivum L.） using a map-based cloning approach was identified as Yr10. Clone 4B of this gene encodes a highly evolutionary- conserved and unique CC-NBS-LRR sequence. Clone 4E, a homolog of Yr10, but lacking transcription start site （TSS） and putative TATA-box and CAAT-box, is likely a non-expressed pseudogene. Clones 4B and 4E are 84% identical and divergent in the intron and the LRR domain. Gene silencing and transgenesis were used in conjunction with inoculation with differen- tially avirulent and virulent stripe rust strains to demonstrate Yr10 functionality. The Yr10 CC-NBS-LRR sequence is unique among known CC-NBS-LRR R genes in wheat but highly conserved homologs （E = 0.0） were identified in Aegilops tauschii and other monocots including Hordeum vulgare and Brachypodium distachyon. Related sequences were also identified in genomic databases of maize, rice, and in sorghum. This is the first report of a CC-NBS-LRR resistance gene in plants with limited homologies in its native host, but with numerous homologous R genes in related monocots that are either host or non-hosts for stripe rust. These results represent a unique example of gene evolution and dispersion across species.
