Supervisor
Dr Nicola Patron
Brief summary
Root system architecture, including the number and density of lateral roots, impacts nitrogen use efficiency (NUE) by maximising N uptake and metabolism. However, it has only been possible to study the influence of larger root systems by comparing different genotypes or by inducing stress. The ability to control root development would enable us to make detailed investigations of the impact of root phenotypes on N uptake and use, and, ultimately, engineer plant resilience. This project will use synthetic biology approaches to precisely tune the expression of key genes to achieve desirable root phenotypes. Our goal is to prime plants to maximise use of applied N, and to quantify how these changes impact N-uptake and use.
Importance of Research
Nitrogen (N) fertilisers ensure high crop yields, but their production and application have negative environmental impacts. Fertiliser not captured by the crop can run off into waterways causing eutrophication. Further, fertiliser production is energy intensive, representing a major challenge to sustainable agriculture. This project is focussed on investigating if synthetic biology approaches can be used to engineer plants that are architecturally and metabolically primed to maximise N uptake, and if this can reduce the requirement for chemical fertilisers.
Project Summary
Nitrogen (N) fertilisers are necessary to ensure high crop yields, but the production and application of fertilisers has negative environmental impacts. For example, fertiliser not captured by the crop can run off into waterways causing eutrophication. In addition, N-fertiliser production is highly energy demanding and cost intensive, representing a major challenge to sustainable agriculture. Root system architecture, including an increased number and density of lateral roots, impacts nitrogen use efficiency (NUE) by maximising N uptake and metabolism. When plants detect traces of N, they extend roots in a foraging response, which we call a N-scavenging phene. Root system size is positively correlated with nutrient acquisition and biomass production, and features such as many long lateral roots increase N uptake. However, it has only been possible to study the influence of larger root systems by comparing different genotypes or by inducing stress. The ability to precisely control root development would enable us to undertake detailed investigations of the impact of root phenotypes on N uptake and use, and, ultimately, engineer plant resilience.
In recent work, the Patron and Brady labs collaborated to elucidate a gene regulatory network that coordinates plant responses to nitrate, showing conservation and divergence across plant linaeges3. This project will use synthetic biology approaches to precisely tune the expression of key genes to achieve desirable N-responsive phenes. This will allow us to prime root systems to maximise use of applied N, and quantify how root systems contribute to improved uptake and use of externally applied N.
What will the successful applicant do?
The student will pursue two objectives. In the first, they will design, build and test synthetic genetic devices to temporarily override N-responses in young plants to induce an N-scavenging phene. To achieve this, the student will be trained in the design of synthetic genetic devices, e.g., toggle switches, cutting-edge DNA assembly techniques, plant transfection and transformation, and quantitative gene expression analysis. In the second objective, they will be trained in use of CRISPR derived technologies for synthetic manipulation of gene expression. They will use these tools to reprogram root development. Engineered plant lines will be carefully characterised using a range of molecular and physiological methods to quantify NUE.
The student will also be mentored to acquire the skills, independence, and confidence they need to reach their career goals, with a focus on the development of skills in scientific writing, critical thinking, time management, collaboration, and communication.
References
Giehl et al (2014) Root nutrient foraging. Plant Physiol. 166, 509–517. doi.org/10.1104/pp.114.245225
De Pessemier et al. (2022) Root system size and root hair length are key phenes for nitrate acquisition and biomass production across natural variation in Arabidopsis. J. Exp. Bot. 73, 3569–3583. doi.org/10.1093/jxb/erac118
Bian et al. Conservation and divergence of regulatory architecture in nitrate-responsive plant gene circuits. bioRxiv 2023.07.17.549299. doi.org/10.1101/2023.07.17.549299