Investigating the Genetic Basis of Seed and Leaf Micronutrient Concentrations in Brassica napus

With a growing population, changing climate and limited new land available, investigating ways to make crops better at using nutrients and boosting yields is becoming a priority. Such work could lead to improvements in human nutrition (i.e. biofortification); the remediation and/or use of contaminated lands (e.g. phytoremediation), as well as general improvements in crop yields. The current research has focused on investigating micronutrient variation in Brassica napus (an important oil seed crop and member of the agriculturally important Brassicaceae). An Associative Transcriptomic (AT) approach was used, exploiting the natural variation in gene sequence and expression amongst a diversity panel of B. napus to explore differences in the seed and leaf ionome. Candidates from AT were validated by testing their orthologous genes with Arabidopsis thaliana T-DNA insertional mutants; if the micronutrient concentration was disrupted relative to a wild type control then the function was validated. After verifying the role of the candidates in A. thaliana, the markers from AT analysis could be exploited in marker assisted selection to improve micronutrient use efficiency. In addition to the AT and A. thaliana analyses in seed and leaf, two other lines of enquiry were investigated. First, the link between the seed ionome and glucosinolates (GSL) was investigated; this research highlighted the disruption in seed ionome caused by breeding for low GSL lines and has implications for its growth under nutrient deficient conditions. Second, the negative association between time to flowering (prior to floral induction) and leaf ionome was investigated with a leaf ionome timeline. This research highlighted a potential link between the age-dependent flowering pathways and leaf nutrient status, however further research is required to assess whether leaf nutrients play an active role in floral induction. It is hoped that such research will aid in the stabilisation of crop yields and reduce fertiliser inputs.