A segment of Triticum militinae chromosome 7G harbors a gene(s) conferring powdery mildew resistance which is effective at both the seedling and the adult plant stages when transferred into bread wheat (T. aestivum). The introgressed segment replaces a piece of wheat chromosome arm 4AL. An analysis of segregating materials generated to positionally clone the gene highlighted that in a plant heterozygous for the introgression segment, only limited recombination occurs between the introgressed region and bread wheat 4A. Nevertheless, 75 genetic markers were successfully placed within the region, thereby confining the gene to a 0.012 cM window along the 4AL arm. In a background lacking the Ph1 locus, the localized rate of recombination was raised 33-fold, enabling the reduction in the length of the region containing the resistance gene to a 480 kbp stretch harboring 12 predicted genes. The substituted segment in the reference sequence of bread wheat cv. Chinese Spring is longer (640 kbp) and harbors 16 genes. A comparison of the segments’ sequences revealed a high degree of divergence with respect to both their gene content and nucleotide sequence. Of the 12 T. militinae genes, only four have a homolog in cv. Chinese Spring. Possible candidate genes for the resistance have been identified based on function predicted from their sequence.
|Original language||English (US)|
|Number of pages||12|
|Journal||Theoretical and Applied Genetics|
|State||Published - Dec 7 2018|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The technical assistance of Marie Seifertová, Radka Tušková, Eva Jahnová and Helena Tvardíková is highly appreciated. This research was financially supported by the Czech Republic Ministry of Education, Youth and Sports (Award LO1204 from the National Program of Sustainability I), by the Czech Science Foundation (Award 18-11688S), the Czech Republic Ministry of Agriculture (Award QK1710302) and by an IUT 193 Grant from the Estonian Ministry of Education and Research. The authors thank the International Wheat Genome Sequencing Consortium (IWGSC) for pre-publication access to IWGSC RefSeq v1.0, the National BioResource Centre (Kyoto, Japan) for providing the CS aneuploid stocks and S. Reader (John Innes Centre, Norwich, UK) for the gift of grain of the ph1b mutant. Access to computing and storage facilities owned by parties and projects contributing to the National Grid Infrastructure MetaCentrum provided under the program “Projects of Large Research, Development and Innovation Infrastructures” (CESNET LM2015042) is greatly appreciated.