Crùbag sat down with scientist Dr Claire Gachon to hear more about her motivations and the Ectocarpus-Eurychasma model that inspired the collection.

Crùbag: Hi Claire, please tell us a little bit more about your research, your motivation, how you came up with this idea and about yourself.

I went into biology simply because I loved it. At the beginning I was very much into animals and insects, then I realised the love of my life was plants. I was studying botany in Paris when fate came in: I fell in love with a seaweed scientist. When I reached the end of my PhD, he already had a position in Oban. It became clear that if we wanted to live together, there was no option but for me to work in Oban, too. So, I kind of jumped into seaweed biology, more by accident than anything else.

During my studies, I was also always interested not just in the living organism itself but also how different organisms interact with each other. It naturally became pathology. You start looking at the plant functioning, then it is attacked by a pathogen and you can look at the interaction from both sides. That’s what I always found most fascinating. But in plant research, you typically have different communities of scientists that work either on the plant side or on the pathogen side. When I started on seaweeds I really wanted to work on both sides. I thought if you only look at one side of the interaction you just miss out so much.

Crùbag: Why did you choose to work with Ectocarpus and Eurychasma? What makes this project so successful?

My idea was to choose a model system where you could look at the interaction between an alga and its pathogen from both sides. It would be relevant to a lot of people, both the seaweed people and the pathologists that work on diseases.

This is why I chose these two organisms. Ectocarpus because it was the first seaweed of which the genome was to be fully sequenced. And despite the fact that it was a very little known oomycete, I chose Eurychasma because it can be compared with other pathogens that are really important like the potato blight, grape mildew or fish saprolegniasis agents. Saprolegniasis for example is a major problem in Scotland because of fish aquaculture being a major export revenue. Therefore the Ectocarpus/Eurychasma model had the ability of attracting a lot of interest from a breadth of very different people. This is what has made it so successful, including helping us secure the funding needed to advance this research.

Crùbag: How did you ensure that the interaction you studied was between these two organisms?

I get asked this question very often. I started to work on this model in the lab in a really controlled way. I was fortunate to be mentored by an emeritus algal scientist in how to obtain and use what we call pure cultures, which contain only the alga infected by its pathogen. In this way, we have as much control as you can ever dream to have in order to tweak the interaction and look into it.

Crùbag: What is the relevance of this model in real life, outside the lab?

This is actually a very complex question. The idea is that at first we needed to simplify it with a lab-controlled system in order to set up our protocols and start to understand how things work. This step has already taken me a few years. Increasingly, what I am trying to do is to apply the knowledge and protocols we have developed in the lab to real life questions. I’m more and more going into the field and designing projects where we start looking at the impact of diseases in the natural environment. For example, something that we are just starting is to look into the patterns of diseases in kelp farms. Kelp farming is something that people in China and other countries actually know pretty well. But not in Europe. Every European country is currently trying to start an entire industry literally from scratch. As soon as you start cropping something you will have diseases. The question for me is: which diseases are going to be important, how do we manage them, and so on.

At the moment we have very patchy pictures of disease patterns even in wild kelp beds. I am pretty convinced that seaweed populations are at least partly regulated in the wild by pathogens. Whether it is Eurychasma or another one, I cannot say. What I can say is that we needed to start somewhere. Establishing this model was a way to start on the bigger story.

Crùbag: Where does your Ectocarpus come from?

Ectocarpus is a very small filamentous alga, maybe a centimetre big, that will grow pretty much everywhere in intertidal areas. You will find it all over the world. Actually, it’s most famous for being a fouling alga, which means it kind of sticks to everything including the boat hulls. It is a big problem because algae growing on the hulls of boats slow them down and increase consumption of fuel. A lot of people would regard Ectocarpus as a nuisance alga (laughs), although there is nothing wrong with it – it’s just growing, you know?

At SAMS, we actually hold a pretty unique collection of Ectocarpus that comes from all over the world. Our favourite Ectocarpus strains come from Chile, Greenland, Brittany, New Zealand and Dunstaffnage, near Oban. Altogether, we have more than 350 different Ectocarpus that have been collected by many colleagues over the last forty years or so. Having access to this fantastic genetic resource played a big part in the decision to use Ectocarpus as a model.

Crùbag: And the Eurychasma?

Claire: We think Eurychasma is a cosmopolitan species found all over the world, but it is very difficult and very labour-intensive to cultivate. There are only very few strains that have ever been brought into culture in the lab, simply because of the time commitment that is required to keep them alive. They essentially come from the places that we’ve gone to and that we sampled, mostly northwestern Europe. I started in Brittany, then moved to Oban so the strains are mostly from Brittany and Oban. One we use for our experiments actually comes from the back beach near our research lab in Dunstaffnage. The oldest one that we have in culture comes from the Shetland Islands and has been in culture since 1996. That is really important for us, because it demonstrates that provided you invest the time and energy you can keep it alive for that length of time.

Crùbag: Oban is a hot spot of Ectocarpus diversity!

There is a lot of Ectocarpus around here near Oban. There is recent research that shows that there are more species of Ectocarpus than are described in the books. We have got colleagues who are very interested in that, who have been going all around the UK sampling in England, Wales, and on the east and west coasts of Scotland. They tell us that Oban is the UK hot spot for Ectocarpus biodiversity. We pretty much have all species here on our doorstep.

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