Triticum aestivum (bread wheat) is an important cereal crop not only in Canada but also worldwide. The pathogen Fusarium graminearum is responsible for causing the disease fusarium head blight and generates yield loses and mycotoxin contaminated grains, including in wheat. A strategy used to mitigate this problem is through the production of FHB resistant wheat varieties by crossing strongly resistant germplasms from closely related wheat species. Thinopyrum elongatum is a wild wheat grass that carries genetic resistance to FHB on the long arm of its chromosome 7E (7EL). Previous work has developed genetic material by crossing Chinese Spring (CS) ph1b line with a CS-7E(7D) substitution line to facilitate introgression of 7E fragments from Thinopyrum into the 7D chromosome of wheat. In the first part of this project a genetic order for previously designed 7EL- and 7D- specific markers was proposed using IWGSC RefSeq v1.0 and was used to characterize the introgressed material from the above cross. Progeny from BC1F7 and BC1F5 families of different lineages were genotyped and phenotyped to characterize regions of introgression which were estimated to be at least 42 and 22 Mbp respectively. Gene expression analysis was also performed for selected 7EL genes. Results showed that the expression of selected 7EL genes present within the introgressed fragments were highly variable between the three families characterized as well as within families. It was also observed that the 7EL introgressed progeny had variable expression when compared to the addition line CS-7EL. Additionally gene expression analyses were also performed using 7D genes. These results showed that there was variation in 7D gene expression between the 7EL introgressed progeny and the controls CS-Fg and addition line CS-7EL-Fg. Possible explanations regarding the variation in gene expression includes differential methylation patterns, silencing of genes in the progeny, alteration of repetitive sequences or activation of transposable elements. Further research will be needed to test these hypotheses.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/38965 |
| Date | 26 March 2019 |
| Creators | Haldar, Aparna |
| Contributors | Ouellet, Therese |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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