The MC-Degradome; a gas-sensing proteome that controls plant development?

Why is it that the life of some proteins is very short, but can sometimes become longer? This proposal focuses on uncovering the mechanisms controlling the stability of proteins, particularly in response to two gases, oxygen, and the signalling molecule nitric oxide (NO). We will discover proteins that require a lack of oxygen or NO to become stable. This is important because there are examples of times during the plant life-cycle, and in response to changes in the environment (for example during flooding) when it is essential that plants can perceive a lack of oxygen or NO. This work will uncover the molecular processes that allow plants to respond to gases and provide molecular resources and conceptual frameworks that plant breeders and growers can use to change plant traits and make plants more adapted to climate change.

We showed for the first time that the N-end rule pathway of targeted proteolysis acts as a key sensor of oxygen and nitric oxide (NO) in plants, by controlling the degradation of group VII Ethylene Response Factor (ERF) AP2-domain transcription-factors (Gibbs et al., Nature 2011, Molecular Cell 2014). The N-end rule pathway controls protein degradation dependant on the amino-terminal residue of a protein substrate. We were the first to identify physiological substrates of this pathway in plants. Our unpublished experiments clearly demonstrate that group VII ERFs are not the only substrates, but that there may exist a unique oxygen/NO regulated proteome, the 'MC-degradome', that profoundly influences plant growth and development. Key hypotheses to be addressed in the project are: 1. There exists a cohort of novel Met-Cys initiating N-end rule substrates; 2. This cohort, the MC-degradome, is co-ordinately regulated by BOTH NO and oxygen. 3. Changes in protein stability are responsible for substrate function. 4. That genes encoding the MC-degradome act co-ordinately to regulate plant growth and development. 5. There remain undiscovered key processes of plant development that are regulated by the N-end rule pathway through the MC-degradome. Outcomes from the work programme: With the proposed work plan we will: Identify a completely novel gas-regulated proteome in plants, the MC-degradome, determine how this proteome controls plant growth and development, and reveal new processes in plants that are regulated by the MC-degradome.

Who will benefit from this research?

Beyond academic audiences where the impact is obvious in terms of increased understanding of how a model plant cell signalling system works, the major beneficiaries of the work described in this proposal will be the commercial private sector and the wider public, and perhaps ultimately the farming sector.

How will they benefit?

If successful our research could in the future lead to the production of crops that have altered characteristics associated with sensing and response to the gases oxygen and nitric oxide (NO). The work described in this application has the potential to be exploited by plant breeders aiming to produce more crops with improved stability of yield, tailored to an increasingly unstable global climate scenario. The commercial arm of our University recognises the importance of our findings and are already engaged in applying for a patent to protect the results arising from our earlier work on the role of the N-end rule pathway in regulating abiotic stress in plants. We will continue to discuss our results with appropriate commercial end users whenever possible to inform them of our findings. For example, we will have a display at Cereals, the leading technical event for the UK arable industry which attracts approximately 30,000 visitors annually.
A wider commercial user group have the potential to benefit as our project will train highly skilled workers for the workforce. We will produce scientifically and computer literate researchers, with excellent oral and written presentational skills.
Engaging with the wider public will be undertaken by all of the investigators and researchers employed on the project. We believe that through our efforts the general public will benefit from a greater knowledge of how plants work and an understanding of how tax payers' money is being used to help contribute towards global food security. To engage with this wider sector of end users, the aims of our work will be presented to visitors to our institution (for example during science week events, university open days and graduation celebrations). We will produce a series of display boards aimed at introducing the general public to the requirement for food security, the need to produce crops with improved agronomic traits, and to outline how modifying gas sensing is likely to impact on this process.