PROJECT

Deciphering organelle transport mechanisms in plants

A multidisciplinary approach to investigate and identify key transporters involved in regulating mitochondrial biogenesis

Plant growth, productivity and seed yield all depend on organelle function which requires metabolites and proteins to be transported across membranes. This mechanism of transport is carried out by specific transporters that have the ability to transport macromolecules, and regulate organelle function.

We have identified new transporters that are involved in amino acid and protein transport in the mitochondria, chloroplast and peroxisomes. We will assign function to each protein and investigate the importance in regulating organelle biogenesis. This will allow us to modulate plant energy production for optimal growth and to withstand abiotic stress, all of which have agriculturally beneficial consequences.

The transport of materials such as metabolites, protein, amino acids, and nucleotides across organelle membranes is a highly regulated and intricate process in the eukaryotic cell. Transmembrane proteins act as gatekeepers regulating and controlling this crucial process, making them essential for normal plant growth and development.

The aim of this proposal is to functionally assess several newly identified transporter proteins located within three essential plant organelles the mitochondria, chloroplast and peroxisomes. We will investigate the transporter function of these proteins and determine their role in plant growth, development and energy homeostasis.

We have generated a range of Arabidopsis thaliana mutant lines that over express key transporters proteins. Biochemical and molecular analysis will be carried out via protein uptake assays and metabolite transport assays. Furthermore the consequences of altering amino acid and protein transporters abundance will be investigated on a transcriptome, proteome and metabolome level.

For more background information, see the suggested readings below.

Suggested readings

Wang Y, Carrie C, Giraud E, Elhafez D, Narsai R, Duncan O, Whelan J, Murcha MW. Dual location of the mitochondrial preprotein transporters B14.7 and Tim23-2 in complex I and the TIM17:23 complex in Arabidopsis links mitochondrial activity and biogenesis. Plant Cell. 2012 Jun;24(6):2675-95.
Murcha MW, Kubiszewski-Jakubiak S, Teixeira PF, Gügel IL, Kmiec B, Narsai R, Ivanova A, Megel C, Schock A, Kraus S, Berkowitz O, Glaser E, Philippar K, Maréchal-Drouard L, Soll J, Whelan J. Plant-Specific Preprotein and Amino Acid Transporter Proteins Are Required for tRNA Import into Mitochondria. Plant Physiol. 2016 Dec;172(4):2471-2490.
Murcha MW, Kmiec B, Kubiszewski-Jakubiak S, Teixeira PF, Glaser E, Whelan J. Protein import into plant mitochondria: signals, machinery, processing, and regulation. J Exp Bot. 2014 Dec;65(22):6301-35.
Wang Y, Law SR, Ivanova A, van Aken O, Kubiszewski-Jakubiak S, Uggalla V, van der Merwe M, Duncan O, Narsai R, Whelan J, Murcha MW. The mitochondrial protein import component, TRANSLOCASE OF THE INNER MEMBRANE17 1, plays a role in defining the timing of germination in Arabidopsis. Plant Physiol. 2014 Nov;166(3):1420-35.
Murcha MW, Wang Y, Narsai R, Whelan J. The plant mitochondrial protein import apparatus - the differences make it interesting. Biochim Biophys Acta. 2014 Apr;1840(4):1233-45.

Project goals

To determine the cellular and intra-organellar localisation of four novel transporter proteins located in the mitochondria, peroxisomes and chloroplasts. These experiments will clarify their distinct localisations and identify putative functions based on interactomes studies.
To understand the physiological role of these transporter proteins for plant growth, development and productivity the abundance of proteins will be modified to investigate their regulatory role with regards to various aspects of plant physiology such as growth, resistance to stress and changes to metabolite composition. This will identify key transporters to manipulate organelle biogenesis and plant cell energy.
To identify the molecular transport capabilities of each transporter protein using new innovative methods such as a yeast heterologous expression system and radiolabelled uptake assays. This will allow for multiple substrate testing to define the functionality and specificity of these transporters.

Research team leader: Dr Monika Murcha

My research focus is to unravel the underlying mechanisms of protein import and macromolecule targeting, key regulatory elements governing mitochondrial activity and thus cellular activity, plant growth and responses to stress. Using a range of genetic, biochemical and molecular approaches the molecular mechanisms that regulate these processes are being investigated.

Collaborations

External collaborators:

Professor Alison Baker, Leeds University
Associate Professor Joshua Heazlewood, University of Melbourne

Handshake

How to apply

Interested in becoming part of this project? Complete the following steps to submit your expression of interest:

Step 1 - Check criteria

General UWA PhD entrance requirements can be found on the Future Students website.

Step 2 - Submit enquiry to research team leader

Given name

Family name

Country

Message

Step 3 - Lodge application

After you have discussed your project with the research team leader, you should be in a position to proceed to the next step of the UWA application process: Lodge an application. Different application procedures apply to domestic and international students.

Scholarships

Scholarship specific to this project

A PhD scholarship valued at $30,000 per annum is available

Domestic students

All domestic students may apply for Research Training Program and University Postgraduate Awards (UPA) scholarships

International students

A range of scholarships are available from international organisations and governments. The full list, organised by country, is available on the Future Students website.

In addition, all international students may apply for International Research Training Program scholarships.

Indigenous students

Indigenous students are encouraged to apply for Indigenous Postgraduate Research Supplementary Scholarships.

Forrest Foundation scholarships

All international and Australian students who wish to study towards the degree of Doctor of Philosophy (PhD) at The University of Western Australia may apply for Forrest Scholarships.

Prestigious postgraduate research scholarships

Prestigious postgraduate research scholarships support graduate research training by enabling students of exceptional research promise to undertake higher degrees by research at the University.