Dissecting heat stress responses in barley

Background: Impact of changing climatic conditions on global crop production. We need to increase the population to feed the world but while reducing the reliance on fertiliser application. One solution is to develop varieties that have improved soil resource capture and thus improved yield under suboptimal conditions. Crop yields are globally affected by abiotic stresses such as drought, salinity and waterlogging. Ubiquitin-mediated proteolysis via the Plant
Cysteine Oxidase (PCO) branch of the PRT6 N-Degron pathway controls the plant response by regulating the turnover of proteins involved in sensing and/or conferring tolerance to abiotic stresses. Root cortical senescence (RCS). Importance of cortical senescence towards this especially improving yield while reducing metabolic burden of maintaining cortical tissues under abiotic stresses. RCS is a very important breeding target for edaphic stress tolerance. The fundamental understanding about genes and mechanisms controlling this process is missing. Interestingly, we recently observed that mutants in PRT6 N-degron pathway have increased RCS. This project focuses on newly discovered and uncharacterized N-Degron pathway substrates to shed light on their specific downstream stress regulation functions, offering new opportunities for stress resilience research. We have previously identified two such substrates, BERF1 and RAF; this project will study their specific roles as key regulators of environmental stress. A recent paper showed RAF and BERF1 were upregulated in a transcriptional analysis, which indicated their important role of these gene in the development of root cortical senescence (RCS). Thus, in this DTP project we aim to dissect this to improve our fundamental understanding about genes controlling this process and identify novel genetic components/solutions that could help us develop varieties tolerant to abiotic stresses.
Work plan:
Year 1: Map the development of root cortical senescence during drought in the mutant and WT.
Decide zones and timepoints for sampling roots and perform RNAseq of mutant vs WT under control and drought stress and sample different zones, including RCS formation to understand genes expressed. Prioritise some candidates' genes based on previous work and its relevance in drought, etc.
Year 2-3: Develop CRISPR, RNAi, reporter lines to validate downstream targets of PRT6 N-degron pathway functioning in regulating root cortical senescence.
Year 3-4. Perform drought experiment in soil columns in Hounsfield facility. Harvest roots for Laser ablation tomography and see whether RCS formation is impaired in the mutant and its impact on the cost benefit of forming RCS in the mutant vs WT. Also study shoot physiological parameters using PhenoSpex trait finder in the Hounsfield facility.
Year 4: Deploy novel genetic solutions to breeding companies.
Project output and impact: This project focuses on newly discovered and uncharacterized N-Degron pathway substrates to shed light on their specific downstream stress regulation functions, offering new opportunities for stress resilience research. This project therefore combines fundamental research into understanding the drivers for abiotic stress resilience, with application to generate resilient barley for deployment.