MSc/Honours projects for 2019
There is an opportunity to undertake one of several projects available for Honours and Masters projects in the Haydon lab for 2019. Projects can be adapted accordingly and all contribute to existing research projects in the lab. Contact Mike for more details and arrange a chat. Follow the links for more information on MSc and Honours programs in BioSciences.
Do WRKY transcription factors regulate plant sugar responses?
Sugars are produced from photosynthesis in a light-dependent manner. They provide the stored energy and building blocks for all cells. In plants, they also have hormone-like properties that regulate developmental transitions and physiology. To understand how sugars regulate gene expression independently of light, we performed a large transcriptome time course to define sugar-regulated transcripts. Gene network and enrichment analyses uncovered WRKY transcription factors, which have previously been implicated in reactive oxygen species- and pathogen-signalling, as potentially important regulators. This project will test whether there is a functional role for WRKY transcription factors in light-independent sugar signalling.
The project aims to:
- Generate transgenic luciferase reporters and measure dynamic gene expression
- Identify regulatory elements in promoter regions using deletion constructs
- Measure reactive oxygen species production and correlate with WRKY gene expression
- Investigate sugar-related phenotypes and sugar-regulated transcript levels in wrky T-DNA mutants
Translational regulation of the circadian clock
Daily rhythms of growth and physiology are controlled by a circadian clock, comprised of a complex gene regulatory network that depends on transcriptional, translation and post-translational mechanisms. In plants, we have an excellent understanding of how transcription is controlled in the circadian oscillator, but little about translational control. By using genetics and transgenic tools, this project will test for a role of translational control of plant circadian rhythms.
The project aims to:
- Introduce circadian reporters into Arabidopsis mutants affecting translational control and measure circadian rhythms
- Test effects of mutations in upstream open reading frames (uORFs) in circadian clock genes on control of circadian rhythms in a transient expression assay
- Isolate transgenic lines complemented with mutated uORF constructs in circadian clock genes
Ethylene signalling in the circadian clock
The circadian clock is a 24-h time-keeping mechanism that allows organisms to anticipate predictable daily events, such as dawn, and synchronise physiology to the environment. Ethylene is a plant hormone that regulates a wide range of plant processes, including fruit ripening and senescence. We have recently discovered that ethylene signalling regulates the circadian clock in Arabidopsis via a pathway that intersects with sugar signalling and converges on the co-chaperon protein, GIGANTEA (Haydon et al Plant Physiology, 2017). We wish to further investigate the role of ethylene signalling components on regulation of the circadian clock and better understand the role of GIGANTEA in this process.
This project aims to:
- Measure effects of sucrose on transcript levels of ethylene-regulated genes
- Generate transgenic luciferase reporter lines for ethylene regulated genes
- Test effects of ethylene and ethylene signalling mutants on circadian clock phenotypes using luciferase reporters and transcript profiling.
- Test effects of ethylene and ethylene signalling mutants on GIGANTEA protein levels
Post-transcriptional control by sugars in the circadian clock
Circadian clocks evolved in all kingdoms of life to synchronise cellular processes to the predictable daily oscillations of the environment. These rhythms are driven by a regulatory network with multiple layers of transcriptional, translational and post-translational control of gene expression. Sugars play an important role in adjusting the phase and amplitude of the circadian clock in plants (Haydon et all Nature 2013; Dalchau et al. PNAS 2011).We have recently discovered that sucrose stabilises a nuclear clock protein, GIGANTEA, by a mechanism that requires an interacting F-box protein, ZEITLUPE to modulate amplitude of the circadian clock (Haydon et al. Plant Physiology2017). We wish to further investigate the role of sugars in the interaction between these two proteins in order to expand our understanding of the effects of sugars on the circadian network.
This project aims to:
- Measure effects of photosynthetic sugars on GIGANTEA protein levels
- Determine effects of sugars on nuclear localisation of GIGANTEA
- Generate split-luciferase reporter lines to detect dynamic protein-protein interactions