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Nitrogen use efficiency in Brassica napus

The aim of this project was to enhance our knowledge of how nitrogen is transported and utilised within Brassica napus through the use of proteomics, phenotyping and genetic mapping. It highlights the importance of looking at all possible plant tissues to determine the mechanisms underlying seven macronutrients (N, P, Mg, Ca, S and Na) and five micronutrients (B, Cu, Fe, Mn and Zn) accumulation, since differences were observed between different tissues. Significant amount of mineral elements were found to remain in both the stem and roots at harvest, which in turn, highlights the inefficient mechanisms applied by some plants in the way they redistribute and utilise minerals such as N, P, K and S. Large genotypic differences in minerals concentration was found between different accessions of B. napus, ranging from 1.48-fold for Ca in the bottom of the stem to 20-fold for Na in top of the stem at maturity. Genotypes were identified that differed significantly from one another in relation to mineral concentration in the stem and root at harvest or in both. Differences were observed in the parents of the TN mapping population allowing a QTL approach to be adopted. Complex network of relationships between minerals were observed within and between tissues, and found to be dependent on the tissue and the growth stage. The strongest significant positive correlations (0.91 > r >0.71) were between Ca/P, S/Ca and N/Ca in taproot, Ca/Mg in stem, and Mg/P and N/S in seed. A significant source of N is that stored within proteins. Several proteins were shown to be accumulated significantly in the top part of the plants especially in the senescing silique walls and the stem adjacent to them. Putative vegetative storage proteins, VSPs, were identified in these tissues and we have suggested that these could be associated with N remobilisation. Development of a screening methodology based on these proteins through which quantitative analysis could be performed on a proteomic based experiment has been successfully developed which will allow the identification of QTLs associated with the N remobilisation and utilisation in plants. These finding could assist plant breeders in developing varieties with enhanced mineral utilisation efficiency. Such developments will eventually lead to significant benefits both economically and socially worldwide as they should lead to increased abilities to enhance crop yields of oilseed rape while lowering the fertiliser requirements.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:731438
Date January 2017
CreatorsGherli, Hussein
PublisherUniversity of Warwick
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttp://wrap.warwick.ac.uk/97639/

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