PhD Studentship: Nitrogen cycling and the control of plant water loss

Nitrogen, the essential plant nutrient, is taken up by roots predominantly in the form of dissolved nitrate. It is assimilated into the plant by the enzyme nitrate reductase which is most active when plants are fast growing, with plenty of light and water. A by-product of the reaction catalysed by nitrate reductase is the cell signalling molecule, nitric oxide (NO). Nitric oxide also has important regulatory roles in eukaryotes being involved in triggering many plant processes, including germination, growth, and stress susceptibility. Together with our collaborators in Nottingham, we have recently discovered that many of the known physiological effects of NO in plants are achieved through the degradation of five transcription factors, the ERFVII family, by a branch of the N-end rule pathway that requires NO to oxidise its protein substrates (Gibbs et al, Mol Cell, 2014). Plants lacking nitrate reductase cannot produce the NO signal properly, their ERFVII transcription factors are not degraded, and these plants are better able to shut their stomata to conserve water when it is scarce.
This project provides an exciting opportunity to use modern molecular techniques to re-examine links between nitrate uptake, nitric oxide signalling, stomatal behaviour and plant water use. The student will determine how the levels of nitrate reductase and the ERFVII transcription factors are regulated through protein turnover. They will be able to track the turnover of nitrate reductase by enzyme assay, western blotting and creating plants expressing a fluorescently tagged version of nitrate reductase; NR-GFP. Excellent facilities for molecular, phenotypic, and nutrient uptake analyses and state of the art plant growth facilities are available in Sheffield and York.

This PhD position is part of White Rose Studentship Network: Water, nutrients and pests – the key drivers to unlocking food security targets. This multidisciplinary network promotes collaboration between the Universities of Leeds, Sheffield and York each of which will host one PhD studentship. Each studentship is bilateral involving two supervisors – the principal supervisor at the lead institution and the co-supervisor at the partner institution.

Students will benefit from being part of an integrated community working upon a larger initiative. The network focuses on three priority areas in agri-science: plant water use efficiency in relation to nitrate cycling (Sheffield - York), understanding how mutualistic plant-fungi interactions change in response to elevated CO2 (Leeds - Sheffield) and development of broad-range bacterial biocontrol application against co-occurring soil-borne pathogens (York - Leeds). Students will discuss their progress their regularly with their supervisors and the whole network will meet formally, to present their work and discuss plans for joint experiments. Students will be encouraged to fulfil the award training requirements at their host institutions and avail themselves of opportunities at the other network institutions. Participation at both national and international conferences will be encouraged.

Funding Notes

Studentships provide full tuition fees at UK/EU student rates for three years, an annual maintenance grant and a contribution towards research and travel expenses to students embarking on full-time PhD programmes.