Expert Breakfast Report for Sept. 27th 2023: Assoc. Prof. Tina Summerfield, Dept. of Botany.

With touches of humour from time to time, Assoc. Prof Summerfield brought to the meeting a contagious enthusiasm for the research work in which she is clearly immersed, with little hints that the offshoots might be of value in carbon sequestration, fuel production and more intensive crop farming.

An unusual start to this session was that Elana asked members not only to introduce themselves to the speaker, but also give a ‘random fun fact’ about themselves, which gave a light-hearted start to proceedings.

Assoc. Prof. Summerfield lectures in CELS191 as well as in various Botany and Genetics courses, and leads a research group of eight people including herself, as well as being Co-Director of Genetics at the University.

She asked the members present where they thought she was from, and the consensus was that she was from the UK, but Tina told us she was surprised at the different reactions she got from New Zealanders, some thinking she was from the UK, and others that she is a Kiwi. Some apparently thinking she only sounded English because she has a friend who speaks with a very definite South African accent!

Early Years

Born in the U.K., Tina undertook a B.Sc in Biological Sciences majoring in Ecology because she had liked it at school, but without giving much thought to what she might do in the future. Because of her dislike of being cold, rather a lot of ecology jobs were not very suitable, which drew her into laboratory work. Since good funding was available for bio-medical research, Tina began her research career working on a project linked to the first sequencing of the human genome. (The human genome project, launched in 1990 involved the collaboration of many scientists from around the world. A high quality, almost complete, sequence was published in 2003. The total cost was estimated at 3 billion $US). As Assoc. Prof. Summerfield pointed out, due to technological advances, it is now possible for a private individual to have their genome sequenced for roughly NZ$500 (but beware of the difference between whole genome sequencing and other types of genetic testing).

“The group I was working with were looking at a particular disease, X-linked hypophosphataemic rickets.” (a condition not corrected by vitamin D administration as is ordinary rickets, and that results in short stature and bow-leggedness). In the search for the gene responsible, Tina’s job was to extract DNA from blood samples, and the group then used some of the tools from the Human Genome Project to search for the gene. “One of the analyses that I did really honed down the region where the gene was. It was very exciting”. She took the result to her boss to show him, but he said he was busy. “I left it on his desk. He came back to her the next day and said, ‘Did you know that was really important?’ I said, ‘Yes, I did!’” The analysis Tina did was obviously very exciting, enabling the group - who had been working on the problem for 8 years - to use a different approach to find the gene.

From there she went to Guy’s Hospital, where they were working on developing mouse models of human disease, where her job was looking after some of the mice, and doing analyses on them. Commuting to work took an hour and a half each way. “I liked my job, but I didn’t love it. The discovery side was fun, but there as also a lot of technical aspects to it, too.” The upshot was that Tina decided to leave London.

She and her partner elected to travel round the world in a year, first going to America, then the Cook Islands, and on to New Zealand. Before they had set off, she had written letters to various Universities (before e-mail was readily available), and received letters back, generating an interview at Auckland, and a job in the Biochemistry Dept. here in Otago, extracting DNA from sheep’s ears as part of an effort to set up a cystic fibrosis model in sheep. Ears had been collected from different sheep and stored in tubes. Her job of removing the ears, scraping off wool and then extracting DNA and analysing it from the skin “ . . wasn’t sweet-smelling!” But it did lead her to think that she wanted more control of her research work, and therefore she started to look for a place to do a Ph.D.

Dunedin and Lichens

“I really loved Dunedin. I loved the pace of life here, and how friendly people are, and how kind they are, compared to how busy London is.” At that time University scholarships were only available to graduates of this University. One of the Professors she knew of had a Marsden grant with associated scholarships, “so I went to see him, mostly because he had some money.” But also she had a friend who was finishing a Ph.D. with this same Professor, who told her how well she got on with him. “For me, getting on with the person you work with is really important, probably more than the project itself. So I jumped from the biomedical project to one looking at lichens.” Lichens are a symbiotic association of a fungus and a photosynthetic organism, which may be a green alga, or a cyanobacterium (1). “The project was looking at whether it was always the same micro-organism with the same fungus, and the reason the project was funded was that in New Zealand there are not many nitrogen-fixing legumes. ” - Some lichens also fix virtually inert atmospheric nitrogen making it available as biologically available nitrogen for plant growth, so it is thought that lichens may be particularly important to the nitrogen cycle in New Zealand.


Tina’s part of the project was to investigate whether it was always the same cyanobacterium associating with the same fungus, or if a number of combinations exist? It turned out that the combinations are quite specific, but in the process she became very interested in cyanobacteria:”. . . because, not only can they photosynthesise and make sugars using carbon dioxide, they can also fix nitrogen." Also, in addition to existing in this symbiotic relationship, the host regulates how much nitrogen product they make, and how many cells are photosynthesising versus the cells that are fixing nitrogen. “I was so interested in how that interaction works - the host over-riding what the cells would normally do. I felt this is the organism I want to work on. I don’t want to work on sheep, or mice or humans, I want to understand more about cyanobacteria. Photosynthesis only evolved once, and that evolution involved an ancestor of cyanobacteria, so they were really pivotal in changing biological life on Earth.”

Cyanobacteria in Climate Change and Fuel Production?

Assoc. Prof. Summerfield went on explain that photosynthesis produced oxygen, leading to the evolution of respiration, and that enabled multicellular organisms. In the present era of climate change, they could also have a role in CO2 sequestration and in producing fuel. “I don’t think we are going to see one single alternative to fossil fuel, but rather a multi-pronged approach to where we get our energy from . . . So, a Ph.D. I just loved it, I had so much fun.” She went on to encourage anyone interested in research to pursue that interest, commenting on the freedom and time one had to concentrate on one particular problem.

Tina completed that work and stayed on for a while looking at photosynthesis by cyanobacteria, particularly the water splitting part, where electrons are removed from the stable molecule water, and oxygen is released. Because water is so stable, this is a very energetically unfavourable reaction. “It’s just the way the protein structure and the catalytic centre are arranged to allow that to happen. We did some work on some of the proteins around there. You can knock them out and see what happens. You can also change single amino acids and see what effect that has. One of the big unanswered questions concerns the two types of photosynthesis. One is oxygenic - it produces oxygen, and the other anoxygenic. Other bacteria use anoxygenic photosynthesis, taking electrons from hydrogen sulphide (H2S). It is much easier to take the electrons from H2S than from H2O, and the photosynthesis systems are much simpler. You’ve got this jump from relatively simple systems to much more complicated ones, with maybe 5 or 6 proteins involved compared to 27 proteins. How they have evolved from each other, we just don’t know . . . So I’m still involved in some of that.”

There are apparently variants that can utilise light in the far red of the spectrum, as you would get in a shaded environment. While such light has lower energy, there are strains of cyanobacteria that can use them for photosynthesis, but with different components in those systems. “So we are looking at how those changes might enable the use of lower energy light.” A potential application of that work could be the introduction of lower energy light systems into plants enabling them to grow closer together. However, their work at present is more concerned with just why changing a particular amino acid changes the electron handling capacity of the system. “So its really very detailed stuff, but I find it very interesting.”

Have Science Degree, Will Travel

Back to her career development, and Tina told us she did some post-doc work in the same Department, then went to the US for another post-doc project. “And I think that’s one of the nice things about science, that it gives you the opportunity to travel, and I went, while my partner stayed here. I went for a year to work on a different cyanobacterial project in the mid-West, and then three years later I came back. So one year became three years, and he was kind of like, ‘Are you coming back to Dunedin?’ So I came back!” Nevertheless, working in a different culture “with a whole bunch of different people” was rewarding. Two projects were involved, one concerning a cyanobacterial strain that exhibited a circadian rhythm, photosynthesising in the daytime, then fixing nitrogen at night, because the nitrogen-fixing enzyme in this particular strain is oxygen sensitive. The project was focussed on how this organism was able to upregulate photosynthesis as daytime approached, then downregulate photosynthesis and upregulate nitrogen fixation as night approached. It apparently does this by employing a circadian clock to activate these events in advance of the light change.

The Saga - and Unexpected Rewards - of Returning to Dunedin

Prior to her return to Dunedin, Tina applied for a post-doctoral scholarship, to which the response was: ”We like you, but not the project.” A second application with a different project drew the response that they liked the project, but were not sure about her! So she put in a third application. She had, however, obtained a short-term six month contract. Arriving in Auckland the news came that her third scholarship application had failed, being placed 13th, with just 12 scholarships available. However, one person in the 12 had also been offered another scholarship which they decided to take instead, thus allowing Tina to slip into the 12th spot. This gave her three years funding to work on cyanobacteria. At the same time a lecturer post cropped up in Botany, and she successfully applied for that, so had to give up the scholarship, reimbursing money already used. This happened in 2009. “If I’m honest, I did it because I wanted a job where I could keep working on the cyanobacteria, that was my main focus . . . but the teaching has been incredible - meeting students, hearing about their journeys and what people are doing, and what you are interested in - and then working with the research students, is brilliant. It’s the part of my job that I wasn’t expecting to enjoy as much as I do. It’s probably the best part of my job now, when you get students especially in a research lab and see them learning all the research skills, coming up with research questions, going off doing brilliant things - that is super-satisfying. And then of course you get the ones who appreciate cyanobacteria as a model, and the ones who love cyanobacteria like I do! ”

Question Time

Asked whether it had been shown that cyanolichens had an effect on nitrogen fixing, Assoc. Prof. Summerfield noted that the post-Doc who was working on that project had been sidetracked by the vexed question of taxonomy of lichens. Historically organisms have been classified according to appearance, cultural characteristics and perhaps some biochemical reactions, but DNA methods available now are showing they have frequently been grouped together - or apart - wrongly. Closely related organisms can behave differently due to the environment they are in. These erroneous classifications can raise significant difficulties in research. However, some Canadian researchers have explored this area with some interesting results. Some combinations of cyanobacteria and lichens can have a significant effect on the nitrogen cycle, “I don’t know about here - but we can look into that.”

Another question concerned the elucidation of the electron transport system, and Tina mentioned a Ph.D. student named Kevin who had worked on this. “It is really hard to predict the effect. What we’ve done is put the far red expressed genes into the normal photosynthetic bacteria, and they do really badly. Then we’ve made single amino-acid changes, and some are really well tolerated when you wouldn’t expect them to be, and others produce chaos in the normal photosystem. What we’ve got now is the crystal structure at really good resolution, so you can now broadly predict effects. In the far red centres the light comes in and you get that transfer of energy between structures . . . we were thinking you could tweak a normal photosystem so it could absorb either normal light or far red light, and I think, at the moment, the ones we produce do not tolerate white light. When we make a change, and when you’ve got normal light it’s just too damaging, so it made the centres perform worse, not better - at the moment.”

Toxic Cyanobacterial (“Algal”) Blooms and Heated Gloves

On the topic of evolving technology, Assoc. Prof. Summerfield noted how powerful Genetics is now, and she certainly expects to use it in future experiments. “Things you only dreamed of being able to do are a reality”. Sequencing technology has moved forward amazingly quickly, along with rapid data processing with smaller and smaller devices. For example as climate change takes a grip, temperature-driven cyanobacterial blooms will become more common. “It’s already happening in the North Island . . . Some of the Regional Councils are seeing blooms all year round.” The salient fact here is that some of these blooms possess genes that makes them toxin-producing, others do not. At the present time, all such blooms are labelled as toxic, whether they are or not, but as their frequency increases, this will no longer be a viable approach.

Tina is very interested in the Oxford Nanopore ‘Minion’ equipment, which is not only portable, but has multiple pores which allows the simultaneous real-time sequencing of multiple pieces of DNA while collecting the data. Given the gene sequence responsible for toxin production, such equipment could conceivably enable rapid identification of the toxin status of any given bloom. The plan is to start work during the Summer, beginning with DNA extraction of known toxin-producing strains they already have, to see if the method will work in this context. Long-term, because the device is portable and can be connected to a laptop computer, they hope to use the method in the field. “We are going to go out with one of the Scientists from the Otago Regional Council and collect samples. So horribly hoping there are going to be some blooms this year!”

As she now owns some battery operated heated gloves to keep her hands warm, going out on ecological forays is no longer as intimidating. Allied to the fact that genetics technology has advanced so much, this makes it easier to connect what is going on in the lab with what is happening in the environment. “And you can do that on a massive scale now, to really get a lot of information about what is happening in a particular environment . . . So for you guys, it’s really exciting . . . I don’t know what is going to happen next. We’ve got this massive ability to understand the basis of disease, or things happening in the environment, in a way that we didn’t before . . . It’s really exciting.”

Use and Misuse of Gene Technology, and Our Contribution

Asked about the potential for unethical use of such technologies, Assoc. Prof. Summerfield first noted there is an International Consortium (2) trying to put some restrictions in place, illustrating the clear need for international legislation. “In New Zealand we are at the moment ‘GE-free’, so all genetic modification . . . is highly regulated . . . It is possible to develop a GMO in New Zealand and release it, but there are a lot of regulatory hurdles . . . There is a big distinction between taking a gene from one organism to another and making that big change, and making changes within the genome of an organism that can occur in nature anyway. I think a lot of countries are regulating those two differently . . . It definitely is a complicated issue. Australia has accepted this genome editing in an agricultural context. From an agricultural perspective, if New Zealand doesn’t make some changes, it will have an economic impact. For you guys, it’s something for you to think about as scientists, so when that discussion does come up, you’ve got an opportunity to inform the discussion, regardless of what you think about it - there is no right or wrong. You’ve got to think about the cultural and ethical issues. It’s definitely going to come up in the next few years. ”

Under-Researched Areas of Gene Editing - and More on Ethics

After commenting that there are people working in all areas, Assoc. Prof. Summerfield, commented, ”There are some I like better than others!” People generally find it easier to accept the idea of gene editing in plants than in animals. The UK is currently changing their regulations so that gene editing, without introducing anything new, can be used in both animals and plants, “to my knowledge the first country to do this.” She told us that one of the big pushes for this change is that introducing a couple of mutations into pigs has been shown to give them resistance to a particular virus infection (Porcine Reproductive and Respiratory Syndrome - PPRS). “It’s a minefield, and people don’t feel comfortable with that, and that should be listened to. There are some great potential benefits in terms of animal welfare . . . difficult to know what is the right thing to do."

Bloopers - and Opportunities Abound!

The final question asked was if Tina had made any major mistakes during her career? “Ah, heaps!,” she replied. Giving this some thought, she added, ”You just have to accept that you’re going to make mistakes. Getting things wrong is just part of being busy, I think, and try to put things in place to minimise that.” She gave an example of presenting a result which was very unexpected, and was challenged as to whether she had got things the wrong way round. She had not. And had indeed checked, double-checked and triple-checked her results. “So I think that checking things . . . but also being kind to yourself. You’re not going to get things right every time. “

Tina went on to describe a few incidents, such as early in her lecturing career when she went in to the classroom and gave out all the handouts, discovering that she was in the wrong class when another lecturer came in, had to collect the now annotated notes back again, find the right group by ringing the Admin. office, get there, and give out the disfigured notes. From then on she always double-checked, down to looking around for faces she could recognise. Yet it happened again! She was in the classroom when a lecturer came in intending to teach music, and determined to do so, even though Tina knew it was her class. In the end they asked the students, “Would you rather learn Music or Botany?!!!”

“It’s an incredibly exciting time to be thinking about science . . . you guys are in a really great position. The things that are going to happen in the next few years are just astonishing.”

[Scribe’s note: Tina mentioned to me afterwards she had been impressed by the standard of questions. I was able to respond entirely honestly that the questions are always good ones!]

Lichens of New Zealand: If you would like to learn a little more about lichens in general terms, there is a free downloadable guide at:

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Posted: Sunday September 24, 2023