Dr Tom Roberts

Summary

I have a passion for understanding the properties and functions of plant proteins, as well as their functionality in foods. While the genomes of an ever-increasing number of plant species have been fully sequenced, the functions of most of the proteins encoded by these genes have not be determined experimentally and many are unknown. The more we understand about the properties and functions of plant proteins, the easier it will be to breed crops that yield high-quality products under a range of biotic and abiotic stresses and to understand how plant proteins affect the properties of food, fibre and other plant products.

Research interests

I am interested in a variety of plant proteins, their properties, roles in the plant, and functionality in foods. My major interest for many years has been the structure, properties and functions of a family of proteins called serpins in plants. Most serpins are potent, irreversible inhibitors of specific serine or cysteine proteases. Serpins are fascinating proteins from many perspectives and have a remarkable variety of functions in animals. The structures and functions of plant and algal serpins are largely unknown but some breakthroughs have been made in recent years - see Ahn et al. (2009), Lampl et al. (2010) listed below, as well as Lampl et al. (2013; doi: 10.1111/tpj.12141). My current work focuses on serpins in barley (with PhD student Nicholas Castro) and wheat. Collaborators in my serpins research include Jørn Hejgaard (Denmark), Robert Fluhr (Israel), Joon-Woo Ahn (Korea), Paul Curmi (University of New South Wales), Brian Atwell (Macquarie University), Peter Sharp (University of Sydney) and Michael Francki (Department of Agriculture and Food, Western Australia).

One of my recent research interests is in the allergenicity of peanuts. Peanut allergy is a major problem in Australia and many other countries; indeed some people (including children) can suffer life-threatening anaphylactic shock upon ingestion of peanuts, even extremely small amounts. The allergens in peanut kernels are seed storage proteins but what determines their absolute and relative abundance in the mature peanut? See my recently accepted paper (Walczyk et al., in press) for one answer to this question. Collaborators are recently completed PhD student Nicole Walczyk (now in Plymouth and Lisbon), Penny Smith (University of Sydney), Euan Tovey (University of Sydney) and Graeme Wright (Peanut Company of Australia).

Another of my interests is the response of plants to an energy crisis. The model system for this work is the rice coleoptile, the sheath that protects the growing shoot from a germinated rice grain. Using oxygen deprivation, either hypoxia (low oxygen) or anoxia (no oxygen), we are able to induce an energy crisis during growth of the coleoptile. Responses studied include energy allocation, transcription (microarrays) and translation (proteomics). Collaborators are PhD student Joshua Edwards (Macquarie University), Brian Atwell (project leader, Macquarie University) and Jim Whelan (University of Western Australia). See my recent paper (Edwards et al., 2012) for an analysis of energy production and allocation in rice coleoptiles under oxygen deprivation.

One of my more recent research interests is in the chemistry and biochemistry of sorghum grain. Collaborators are PhD student Ali Khoddami, Meredith Wilkes (formally University of Sydney) and Peter Selle (University of Sydney). My other new research topic is the physiological response of cotton plants to flooding. Collaborators are PhD student Najeeb Ullah, Daniel Tan (project leader, University of Sydney) and Brian Atwell (Macquarie University).

To pursue these interests my research involves a broad range of techniques in plant physiology, cell biology, molecular biology and biochemistry. Techniques employed recently include radiolabelling, confocal microscopy, microarray analysis, RT-PCR and 2D-DIGE. Bioinformatics analysis is involved in many aspects of my projects.

Please contact me if you are interested in pursuing a PhD in one of the above topics.

Background

After studying at James Ruse Agricultural High School in Sydney, I completed a BScAgr Honours degree at the University of Sydney in 1988, in which I majored in Agricultural Chemistry. I then received an Alexander Hugh Thurburn PhD scholarship and graduated with a PhD thesis entitled “Glyoxylate aminotransferases and ureide catabolism in the developing fruits of legumes” in 1995.

After my PhD research I worked as a Postdoc at Lund University, Sweden (1994-5) on the properties and functions of the multiple NAD(P)H dehydrogenases in plant mitochondria. Back in Sydney I then worked in food chemistry, developing novel methods for the purification of pharmaceutical-grade lactose from cheese whey at the University of Western Sydney/CSIRO North Ryde (1995-6). I returned to Scandinavia and worked as a technical editor at Lund University and at the Royal Agricultural and Veterinary University in Denmark, as well as a Research Scientist at Novartis Seeds in Sweden. I then secured a 3-year Research Fellowship (1997-2000) at the Risø National Laboratory and the Technical University of Denmark on the properties and functions of serpins in barley and wheat.

Returning to Sydney in late 2000, I worked as a Research Fellow in the Macquarie University Centre for Analytical Biotechnology and conducted research on the mechanism, structure and regulation of magnesium chelatase, a key enzyme in (bacterio)chlorophyll biosynthesis. I also gained experience in university teaching at Macquarie University and at the University of Sydney. In 2004 I secured an ongoing lectureship in the Department of Biological Sciences and then in the Department of Chemistry and Biomolecular Sciences at Macquarie University. I was a Key Researcher in the Grain Foods CRC, which ended in 2009, the same year in which I became Senior Lecturer at Macquarie University. I taught a range of units there including 2nd-year Plant Structure and Function, 3rd-year Cell and Developmental Biology and 3rd-year Plants: Cells and Molecules.

I took up a Senior Lectureship at the University of Sydney in January 2012. I am Principal Supervisor of Ali Khoddami (sorghum chemistry and biochemistry) and Nicolas Castro (proteomics of barley malt) at the University of Sydney. I continue to supervise Nicole Walczyk (a PhD student working on peanut allergens and Julian May (an Honours student working on serpins in rice coleoptile senescence) at Macquarie University. I am Associate Supervisor for a PhD student (Joshua Edwards) working on energy metabolism in rice coleoptiles at Macquarie University. I coordinate 2nd-year Plant Biochemistry and Molecular Biology and 3rd-year Chemistry and Biochemistry of Foods, and teach parts of 3rd-year Food Biotechnology and the Masters unit, Principles of Biochemical Analysis.

Recent publications

• For a more detailed list of my publications (with citations), please see my ISI Researcher Profile at http://www.researcherid.com/rid/H-2071-2012 or my Google Scholar profile at http://scholar.google.com.au/citations?user=wjMj6fMAAAAJ&hl=en.
• Walczyk NE, Smith PMC, Tovey E, Wright GC, Fleischfresser DB and Roberts TH (in press). Analysis of crude protein and allergen abundance in peanuts (Arachis hypogaea cv. Walter) from three growing regions in Australia. Journal of Agricultural and Food Chemistry
• Khoddami A, Wilkes MA and Roberts TH (2013). Techniques for analysis of plant phenolic compounds. Molecules 18, 2328–2375
• Edwards JM, Roberts TH and Atwell BJ (2012). Quantifying ATP turnover in anoxic coleoptiles of rice (Oryza sativa) demonstrates preferential allocation of energy to protein synthesis. Journal of Experimental Botany 63, 4389–4402
• Francis SE, Ersoy RA, Ahn J-W, Atwell BJ and Roberts TH (2012). Serpins in rice: protein sequence analysis, phylogeny and gene expression. BMC Genomics 13, 449
• Vella NG, Joss TV and Roberts TH (2012). Chilling-induced ultrastructural changes to mesophyll cells of Arabidopsis grown under short days are almost completely reversible by plant re-warming. Protoplasma 249, 1137–1149
• Fluhr R, Lampl N and Roberts TH (2012). Serpin protease inhibitors in plant biology. Physiologia Plantarum 145, 95–102
• Roberts TH, Lampl N and Fluhr R (2011). Plants and the Study of Serpin Biology. Chapter 17 in Whisstock JC and Bird PI: Methods in Enzymology 499, 347–366
• Lampl N, Budai-Hadrian O, Davydov O, Joss TV, Harrop SJ, Curmi PMG, Roberts TH and Fluhr R (2010). Arabidopsis AtSerpin1: crystal structure and in vivo interaction with its target protease RESPONSIVE TO DESICCATION-21 (RD21). Journal of Biological Chemistry 285, 13550–13560
• Jerkovic A, Kriegel AM, Bradner JR, Atwell BJ, Roberts TH and Willows RD (2010). Strategic distribution of protective proteins within bran layers of wheat (Triticum aestivum L.) protects the nutrient-rich endosperm. Plant Physiology 152, 1459–1470
• Ahn J-W, Atwell BJ and Roberts TH (2009). Serpin genes AtSRP2 and AtSRP3 are required for normal growth sensitivity to a DNA alkylating agent in Arabidopsis. BMC Plant Biology 9, Article 52 (11 pp)

Contact

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