Keeping the global population fed in times of climate change and population growth is considered to be one of the greatest challenges of the 21st Century. Plant stress is defined as any external factor that negatively impacts on growth, productivity, reproductive capacity or survival. The use of salinized water in agriculture is likely to become a more regular occurrence, as diminishing freshwater supplies are available for crop irrigation. High salt drastically affects growth and it is therefore necessary that crops be bred to be able to withstand such adversity. Recent advancements in technology allow us to measure gene expression on a genome wide scale, techniques resulting in the development of theoretical models of regulation and the identification of key regulatory genes have been used in Arabidopsis. There is need to transfer this knowledge from model plant to crop, ensuring the application of such technologies to the issue of food security. A large microarray experiment was performed during this project in which the expression of over 60,000 genes were measured in Brassica oleracea GD33DH over a period of 36 hours following salt shock. The use of bioinformatics tools allowed the identification of 7,141 significantly differentially expressed genes in the early response to salt shock in GD33DH. Additional information on the time of differential expression revealed potential genes and mechanisms indicating that metabolism was highly affected by salt shock. Germplasm from crop wild relatives in breeding programmes is a crucial source of genetic material to replace variation lost through years of selective breeding allowing the development of crops with higher stress tolerance. By screening a collection of wild C-genome Brassica species for salt shock tolerance, tolerant germplasm was identified and sequenced alongside susceptible germplasm. Comparative analyses revealed the genes and mechanisms used by wild Brassica species protect themselves from the adverse effects of salt shock. Whole genome duplication events occurring in the recent evolutionary history of C-genome Brassica was examined whereupon it was found that stress specific duplicate genes are on average expressed more highly than single copy suggesting that WGD has implications on the response to stress. These results provide a wealth of potential gene targets for future study and germplasm that can be used in the development of stress tolerant B. oleracea varieties.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:714935 |
| Date | January 2016 |
| Creators | Hicks, Christine P. |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/88809/ |
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