The overarching theme of our research is to determine the controls and regulators of communication between the chloroplast and nucleus. This includes discovery of genes and metabolites involved in epigenetics, RNA metabolism, chloroplast-nuclear signaling, carotenoid biosynthesis, photosynthesis and drought.
The research program is an integral component of the ARC Centre of Excellence in Plant Energy Biology. The Centre offers Honours scholarships ($6K) and top-up scholarships for PhD students ($7K), in addition to well funded research, conference travel and graduate training programs.
1. Signaling during chloroplast development
- First demonstration of a role for the cytoskeleton and a novel cytoskeleton-associated protein in chloroplast biogenesis (Albrecht et al 2010, Plant Cell). Elucidation of a mechanism for photosystem assembly that requires lipid vesicles and a protein disulphide isomerase that folds light harvesting and other photosystem proteins (Tanz et al. 2011, Plant Journal).
2. Identification of the first signal to move from the chloroplast to the nucleus
- We are studying the mechanisms by which plants perceive and respond to drought and excess light. Recently, we uncovered a molecule that moves between the chloroplast and nucleus to regulate gene expression. The key publication is Estavillo et al 2011, Plant Cell, which builds upon Marin et al 2011 Plos One, Wilson et al. 2009 Plant J. and Rossel et al 2006.
3. Intersection of drought and high light signaling
- Demonstration of a role for the ER and an ER processing protein in chloroplast-nuclear communication, specifically in response to drought (Che et al. 2010, Science Signaling)
- Commercial outputs. The knowledge of the SAL-PAP retrograde pathway has been published (Rossel et al. 2006, PCE Wilson et al. 2009, Plant Journal), patented and is being applied to the development of drought tolerant wheat in collaboration with CSIRO and GRDC and in Canola with Pacific Seeds via an ARC Linkage grant.
Also see Gonzalo Estavillo's web page.
4. Epigenetic regulation of carotenoid biosynthesis
- Carotenoids, such as beta-carotene, are essential for photosynthesis, dietary vitamin A and as antioxidants offer protection against certain cancers and age-related blindness. We made the first identification of an epigenetic regulator of carotenoid biosynthesis. Communication between the chloroplast and nucleus occurs in both directions and a seminal finding was the identification of a histone methylation transferase that regulates specific enzymes required for carotenoid biosynthesis, flowering time and hormone synthesis in the chloroplast. Future goals are to elucidate the epigenetic controls and identify novel carotenoid-derived retrograde signals produced from carotenoids that regulate nuclear gene expression and plant development. See Cazzonelli et al. 2009 Plant Cell and Cazzonelli web page.
5. Leaf to leaf systemic signalling
- A leaf exposed to full sunlight will transmit a signal to shaded leaves enable a systemic acquired acclimation (SAA) response. The nature and regulation of SAA is under investigation.
6. Photosynthesis and photoprotection
- We are investigating the safety valves plants used to protect against oxidative damage induced during photosynthesis. This program is a combination of biochemical genetics and physiology using Arabidopsis and avocado.
7. Collaborative projects
- Several projects are undertaken by students based in CSIRO. For example, there is a project relating to cereal colour and nutritional content of wheat with Dr Crispen Howitt.
- A key to our research is teamwork and applying cutting edge molecular and biochemical techniques in combination with whole plant physiology to build a picture from gene to crop.The approach utilizes deep sequencing, microarrays, promoter-reporter gene fusions, HPLC and GC-MS to identify novel genes and signalling pathways in Arabidopsis (related to Canola), wheat, avocado and canola.
- The Hunt for RNA Riboswitches and Genetic Sensors of Metabolic Flux in Plants (Secondary Investigator)
- Towards improving the role of canola and other Brassicas during drought (Primary Investigator)
- Pogson, Estavillo and Yadav 'The generation of wheat cultivars with improved drought tolerance' Grains Research Development Council