University science: plant respiration and a mentor's insights

After finishing year 12, you went on to your science degree at the Australian National University. What subjects did you study?

My first year was probably fairly standard: physics, maths, chemistry, some biology. But pretty soon I decided that chemistry and physics were a bit dry for me, the lectures for mathematics were far too early in the morning, and biology was definitely the answer. The biology lecturers were really enthusiastic and enjoyable; the science seemed to be really new – everything was just being published, just being discovered – and that caught my imagination.

You went on to do Honours and a PhD, also at the ANU.

I did, yes, in David Day's laboratory. During my Honours and then a PhD – again linked with CSIRO – I looked at a process within respiration in plants. To describe that a little bit: we tend to understand respiration in terms of our own breathing as a gas exchange. So we breathe in oxygen, we breathe out carbon dioxide and water. But in fact that process of using the oxygen and producing the CO₂ and water is happening in every cell of our bodies. This process of making energy happens in most organisms, and in plants we were looking at how the process is regulated – how the plant actually makes its energy, when it makes it and what it uses it for.

Was your Honours and PhD supervisor important as a mentor during this time?

He was indeed. I met David Day when he lectured me as an undergraduate, in second year. (I really enjoyed his lectures, even though he seemed to think I wasn't very interested in them.) He asked me to work in his lab for a summer project at the end of my second year, and said he would pay me. 'Well, this is great,' I thought, and taking up his offer sparked a lasting friendship.

I learnt a lot from him, especially about how science works. The key thing was that science unpublished is science half-done, because science is really about communication. It is all very well to find something out, but if you don't tell people about it you haven't fulfilled your job as a scientist.

Oxford studies in mitochondrial proteomics

What did you do after completing your PhD?

I stayed on in Canberra for a few months, finishing various pieces of work at ANU, and then a few opportunities came up for me to go to Europe on a research fellowship. In the end, I went on a Human Frontier Fellowship to work in a plant respiration lab in Oxford.

There we started to use some tools that I hadn't used previously. A key one was an attempt to move away from the usual very reductionist approach of looking at just a couple of the elements of respiration. The challenge I found there was to work at a holistic level in a plant (or any organism, for that matter) – that is, to take these broad approaches but also to understand how things work at a molecular level.

The technique or approach we were using was proteomics, which may sound odd but has a history in the understanding of genomics. For many years people have realised that you can take a gene which is the blueprint for making a particular protein, and sequence the gene – that is, work out exactly everything that is in it, its entire blueprint. More recently, scientists have found that you don't have to work on just one gene from an organism; you can work on all of its genes and thereby sequence its whole genome. The study of that whole genome is called genomics. This is now possible in a number of model systems – plant systems, bacteria, viruses, worms, flies, and now even humans themselves as the human genome has been sequenced.

But people have realised that the blueprint for everything that an organism could possibly do doesn't actually tell you what the organism is doing at a particular time in a particular place. That is where proteomics comes in: it is a study of all the proteins – a study of everything that a plant or animal, whatever it might be, is doing at a particular time. So that's what we were trying to do.

Why is this work important?

First, it is very important that we understand how genomes work, and how organisms actually use their genetic information to cope with the environment they are in. And, second, our particular interest in respiration was to understand how it is that plants provide the energy they need, at exactly the time when they need it.

One critical thing is that the place where respiration actually happens is in the little structures inside the cells called mitochondria. These are what are 'doing' respiration. People have found out recently that these are involved not only in producing energy but in the decision of cells to die. Often a cell makes a strategic decision to die for the good of the whole organism. Mitochondria have been called 'the breath of life and the kiss of death', and understanding how they and their proteome respond to different conditions is quite important in understanding how plants really tick.

Focus questions

• What is the role of mitochondria in a cell? What types of organisms have mitochondria within their cells?

• How is the information from proteomic studies related to information from genomic studies?