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Gene expression analyses help elucidate positive selection in cultivated crops and early seedling responses to thiamethoxam and neighbouring turf grass

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dc.contributor.advisor Lukens, Lewis
dc.contributor.author House, Megan
dc.date.accessioned 2016-01-08T20:28:35Z
dc.date.available 2016-01-08T20:28:35Z
dc.date.copyright 2016-01
dc.date.created 2016-01-07
dc.date.issued 2016-01-08
dc.identifier.uri http://hdl.handle.net/10214/9475
dc.description.abstract This thesis investigates the role of gene expression in crop evolution and crop responses to environmental variation. It applies both retrospective and experimental approaches to examine how changes in gene expression contribute to plant improvement. Using a retrospective approach, I identified genes whose regulatory alleles were selected during the breeding of elite rice varieties. Selection for groups of genes with shared attributes likely altered oxidative stress responses and amylase activity. I also identified 31 genes that have strong-acting trans regulatory factors and may have been selected for increased or decreased expression in rice breeding. In maize, I then used a high-throughput sequencing approach to identify candidate genes from seedlings that have a transcriptional response to experimentally manipulated weed competition (turf grass). Weed competition altered transcript abundance of 102 genes. Gene function annotation indicates that genes related to carbon metabolism, ROS-scavenging, hormone signalling and defence are involved in the early response of maize to the weed treatment. With the wide-use of neonicotinoid insecticides, I was also interested if thiamethoxam, a component of a popular insecticide used for maize, has an effect on seedling response to weeds. I tested for an interaction between seedling response to weeds and the thiamethoxam treatment, and found that thiamethoxam affects the response of genes involved in photosynthesis, defense, and hormone signalling. I believe that candidate genes from both approaches will be useful for future breeding efforts. en_US
dc.language.iso en en_US
dc.subject eQTL en_US
dc.subject artificial selection en_US
dc.subject lineage-specific selection en_US
dc.subject low R:FR en_US
dc.subject weed competition en_US
dc.subject thiamethoxam en_US
dc.title Gene expression analyses help elucidate positive selection in cultivated crops and early seedling responses to thiamethoxam and neighbouring turf grass en_US
dc.type Thesis en_US
dc.degree.programme Plant Agriculture en_US
dc.degree.name Doctor of Philosophy en_US
dc.degree.department Department of Plant Agriculture en_US
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