Genetic and molecular characterisation of the regulation of plastid import protein Toc159 - AfS, ENWW

Plastids are a family of specialised cellular compartments that are found in plants and algae. The best studied plastid is undoubtedly the chloroplast, which is the site of photosynthesis in all green plants. Plastids have an unusual ancestry - they are descended from once free-living photosynthetic bacteria. Over the course of evolutionary history, plastids have become completely dependent on their hosts, ceding most of their protein-encoding genes to the central, nuclear genome. These proteins must therefore be transported back into the plastid after synthesis, and this is facilitated by a dedicated machinery (the TOC/TIC complexes). Over the last few years, it has emerged that the TOC complex is actively regulated by the Ubiquitin Proteasome System (the UPS), a system which targets proteins for degradation via the transfer of a specialised tag. This regulation has a major role in both plant development and responses to stress. To complement this work, I propose to search for additional regulators of the TOC complex, and to investigate whether or not the SUMO system (which is both evolutionarily and mechanistically related to the UPS) also regulates plastid import. This work is important as an in-depth understanding of plastid function and behaviour is key to understanding the physiology of plants, and could pave the way for innovative crop improvement strategies.

The proposed project falls within the remit of one cross council and two BBSRC priority areas. As basic plant biology underpins the development of novel crop varieties, this project can be considered to be furthering the goal of 'Sustainably enhancing agricultural production'. Indeed, results generated by projects similar to the one here proposed are currently being explored by our lab in a translational context. By the same logic, this project falls within the remit of 'Global Food Security' and 'Food, nutrition, and health', which are cross council and BBSRC priority areas respectively.