Our research is focused on the biogenesis and functions of chloroplasts (plastids) in plants. Areas of particular interest are: the import into chloroplasts of nucleus-encoded proteins; and, ubiquitin-dependent proteolysis via a process called CHLORAD (chloroplast-associated protein degradation). As a DPhil student in our group, you would be part of a well-funded research team conducting pioneering research in these areas. Details of the project would be defined through discussions between the student and supervisor; what follows below is a summary of the research interests of the group.
Plastids are a diverse family of plant organelles with numerous functions that are vital for plant growth. The family includes chloroplasts (responsible for photosynthesis), and a range of non-photosynthetic variants such as starch-containing amyloplasts in seeds, tubers and roots, carotenoid-rich chromoplasts in flowers and fruits, and chloroplast-precursor organelles in dark-grown plants called etioplasts [1]. Most plastid proteins are encoded by the nuclear genome and synthesized in the cytosol as precursors with N-terminal targeting peptides. Import of precursors into chloroplasts is mediated by the TOC-TIC translocons [1].
We seek to understand these import systems mechanistically, and in particular their proteolytic regulation via CHLORAD. To do this we apply a full spectrum of molecular, cellular, genetic, biochemical and computational approaches, and we study the model plant Arabidopsis thaliana as well as a range of crop species.
A major breakthrough was the discovery that plastids are directly regulated by the ubiquitin-proteasome system, defining an important new area of cell biology [2]. First, we identified a ubiquitin E3 ligase in the plastid outer membrane called SP1, and showed that it targets the protein-import machinery for degradation [3]. Then, we revealed that SP1 is part of a broader system termed CHLORAD, which incorporates a protein ‘retrotranslocation’ system to enable proteolysis within the cytosolic proteasome. By regulating the protein-import machinery, CHLORAD controls the plastid’s proteome, functions and developmental fate (e.g., which plastid variant is formed) [1,3,4].
However, many mechanistic details of the CHLORAD pathway remain to be elucidated. Our discovery of CHLORAD suggested novel crop-improvement strategies. CHLORAD is required for developmental transitions in which plastids change function [3,4], and so potentially has diverse agricultural applications, e.g., during fruit ripening in crops like tomato, when chloroplasts transform into chromoplasts [5], or during grain development in crops like wheat and rice, when amyloplasts are formed [1,6]. Manipulating CHLORAD activity may allow greater control over such processes.
Our work also revealed an important role for CHLORAD in plant stress tolerance, which it promotes by attenuating the formation of harmful reactive oxygen species [4,7]. Thus, manipulating CHLORAD may enable development of stress-tolerant crops, which is a particular priority in low/middle-income countries and in the context of climate change [8].
This project is part of the Molecular Plant Biology section in the Department of Biology.
References
References
- Jarvis, P., López-Juez, E. (2013) Nat. Rev. Mol. Cell Biol. 14:787-802.
- Sun, Y., Jarvis, P. (2023) Ann. Rev. Plant Biol. 74:259-283.
- Ling, Q., Huang, W., Baldwin, A., Jarvis, P. (2012) Science 338:655-659.
- Ling, Q. et al. (2019) Science 363: eaav4467.
- Ling, Q. et al. (2021) Nat. Plants 7:655-666.
- https://www.oxfordsparks.ox.ac.uk/content/changing-plant-chloroplasts-improve-crop-performance
- Ling, Q., Jarvis, P. (2015) Curr. Biol. 25:2527-2534.
- https://www.oxfordsparks.ox.ac.uk/content/hardy-crops-tackle-food-insecurity
Funding
This project is part of the DPhil in Biology programme, and is not a funded course at the University of Oxford; as such, students are expected to explore options for funding. However, we anticipate being able to offer around 6 full graduate scholarships to incoming DPhil students in 2026/27.
You will be automatically considered for several Oxford scholarships, which cover fees and stipend, if you fulfil the eligibility criteria and submit your graduate application by 8 January 2026. Scholarships are awarded based on academic achievement and potential to excel as a DPhil student.
For further details about searching for funding as a graduate student visit the graduate study information on our website.
Eligibility
For full entry requirements and eligibility information, please see the main admissions page.
How to apply
The deadline for applications for 2026/27 entry is midday 8 January 2026. We will continue to accept applications submitted after this date, but these late applications will not be considered for scholarship funding.
You can find the admissions portal and further information about eligibility and the DPhil in Biology Programme at the University's graduate admissions page. Please quote the Project Reference Code alongside the title in the ‘Proposed field and title of research project, if applicable’ field in the application form.
Institution website: https://www.biology.ox.ac.uk/dphil
- Primary supervisor: Paul Jarvis
- Primary supervisor contact: paul.jarvis@biology.ox.ac.uk
- Submission deadline: 8 January 2026
- Funding: Competition-funded
- Tags: Cell biology, molecular biology, genetics, plant physiology, protein biochemistry, structural biology, agriculture, chloroplast biogenesis, organelle biology
- Project code: PJ01
