Transcriptional control of GABA signalling in plants
Examine regulation of enzymatic pathway gene transcription in plants in response to changing environments.
Being sessile, plants have evolved complex signaling mechanisms to cope with the range biotic and abiotic stresses to ensure survival. One such mechanism involves the non-protein amino acid Gamma-aminobutyric acid (GABA) that acts as a signal to modulate plant growth and response to stress. GABA is produced from the decarboxylation of glutamate by glutamate decarboxylase (GAD) enzyme and rapidly accumulates in response to environmental stress. While the enzymatic pathway that leads to GABA synthesis in plants is well documented, very little is known about the transcriptional regulation of GAD genes and how GAD expression respond to changing environments.
The proposed Honours project will seek to understand the regulatory mechanism controlling GAD gene transcription. The study will involve computational analysis of GAD promoter sequences and co-expression network analysis to identify candidate transcription factors that enhance or repress GAD transcription. Candidate transcription factors will be tested for GAD activation in plants using a transgenic luciferase reporter system and yeast-one-hybrid analysis. The project will be undertaken in the Centre of Excellence in Plant Energy Biology () with an intensive focus on molecular biology techniques to understand GABA regulation in plants.
You will develop skills in:
- Molecular techniques including DNA and RNA extraction, gene cloning, PCR, quantitative RT-PCR, yeast one-hybrid assay
- Transient transformation of promoter fusion constructs in Nicotiana benthamiana (tobacco) and stable transformation in Arabidopsis
- Bioinformatics skills including phylogenetic and in silico analysis of promoter sequences for key GABA related genes, co-expression analysis to identify candidate transcription factors
- Fluorescence microscopy to observe luciferase reporter constructs
Ramesh, SA., et al. (2015). GABA signalling modulates plant growth by directly regulating the activity of plant-specific anion transporters. Nature Communications 6: 9.
Gilliham M, Tyerman SD (2016). Linking metabolism to membrane signalling: The GABA-Malate connection. Trends in Plant Science 4:295-301