Liam Dolan is a Group Leader at the Gregor Mendel Institute of Molecular Plant Biology (GMI) in Vienna, Austria, interested in intersection of plant development, evolution and ecology using the emerging model system Marchantia polymorpha. We met with Liam at the GMI to learn more about his career so far, his views on biodiversity and the ecosystem, and why he became involved as a Guest Editor for Development's Special Issue: Uncovering Developmental Diversity.

When did you first decide to become a scientist and pursue a PhD?

I was intrigued by the natural world as a child and thought that I might have fun studying biology at university. I had some inspiring teachers at University College Dublin. They showed me how to frame questions about the natural world and how these questions could be answered through research. I did a botany degree and enjoyed discovering morphology and morphological diversity. But, even as an undergrad, I was aware that we did not understand how this diversity of forms developed. I read a short news article in a scientific journal reporting on progress at a meeting on plant development. One of the names mentioned was Scott Poethig at the University of Pennsylvania. I wrote to Scott and I visited Pennsylvania. A year later I joined the Biology PhD programme at Penn.

Could you tell me about your thesis project at the University of Pennsylvania, USA, and postdoctoral work at the John Innes Centre in Norwich, UK?

Scott was fantastic; we formulated two projects. One was on leaf development in cotton that I wrote up for my PhD (Dolan and Poethig, 1991), and the other was in Arabidopsis and became the basis for my postdoc work in Norwich, UK, with Keith Roberts (Dolan et al., 1993, 1994).

The idea to work on Arabidopsis root development occurred to me around eight o'clock one night in Scott's lab. I was working late growing Arabidopsis seedlings and looking at the development of the leaves in a variety of mutant backgrounds because we were thinking of developing a project on leaf development. For some reason, I decided to look at the roots. I discovered that the root epidermis of Arabidopsis develops a beautifully patterned array of root hair cells and non-hair cells, typical of members of the Brassicaceae family. I decided to carry out a mutant screen looking at Arabidopsis mutants with defective root epidermal development. I spent the next 25 years working on genes identified in this screen. The most important genes we found act downstream of the patterning process that specifies cell fate. ROOT HAIR DEFECTIVE6 positively regulates the development of root hair cells in Arabidopsis roots. We've shown that this is a function that's conserved among all land plants. Our working hypothesis is that ROOT HAIR DEFECTIVE 6-LIKE (RSL) genes act in the last common ancestor, where they promote the development of tip-growing rooting cells – root hairs and rhizoids. Combining developmental genetics with palaeontology, we now think that these RSL genes controlled the development of the rooting structures of the first land plants.

Why did you decide to go from the John Innes to Oxford, and then Vienna?

I'd been at John Innes for 18 years, and my research had been influenced a great deal by mentors like Keith Roberts and Peter Shaw, two extraordinary cell biologists. I felt that, as our evolutionary biology research was developing, it might be good to go somewhere where there was more phylogenetics. I was in Oxford for 11 years and my ideas were influenced by colleagues around me, not only in plant science but by colleagues from other disciplines such as zoology, earth sciences and chemistry. Here at GMI, there are eight independent research groups. I've got direct collaborations with four of those. Being here allows me to explore the genomic basis of morphological diversity. In particular, it allows me to focus on fundamental discovery research. When I look back at each move I have made, there has been scientific motivation. However, each move has also been an exciting personal experience.

Every year, I ask myself, ‘am I happy here?’

Would you encourage other group leaders to move around from time to time?

Yeah, if possible. I was lucky because I was in a position where I could move. Every year, I ask myself, ‘am I happy here?’. If the answer is no, I try to find out what would make me happy. Having tried that, if I feel like I'd be happier somewhere else, then I explore my options. I want to actively decide to stay in a place rather than passively staying.

What was it like to move to Vienna after living in the UK for so long?

It's exciting. My knowledge of German is good enough to allow me to listen to and understand programmes on the radio and read newspapers. My spoken German is improving slowly. It's been very interesting looking at the two small islands on the west of Europe from the viewpoint of Central Europe – Ireland and Britain look very different from here. Vienna is also a capital city in which you can afford to live; this makes the city attractive to postdocs, graduate students and interns. Infrastructure is good. No place is perfect, but Vienna ticks a lot of boxes.

How easy is it to move a lab?

It's very stressful – there are no two ways about it – because you're moving your personal life and your science in a limited number of boxes. Moving during the COVID-19 pandemic was an added challenge – we moved in September 2020. We lost a number of genetic stocks because of the combined lockdown and, consequently, lack of access to the lab and the move to Vienna. However, once we arrived, we got up and running very quickly. Moving also becomes an excuse to declutter and refocus. We've changed emphasis in our research since moving to Austria; we're still asking the same fundamental question, but pivoted a little.

Are there challenges in working with an untraditional model organism such as Marchantia?

When you start research on a new system, trivial things can hold you up. For example, getting Marchantia to go through the lifecycle in incubators can be a challenge. However, we've benefitted a lot from the fact that, a few years before we started, Takayuki Kohchi and colleagues at Kyoto University established simple plant husbandry methods and T-DNA transformation methods for Marchantia. This allowed us to generate large insertional mutant populations and manipulate gene function. Furthermore, the Marchantia community is very generous, welcoming and collaborative, which allowed us to make rapid progress early on.

When you start research on a new system, trivial things can hold you up

You recently joined Development as a Guest Editor for the Special Issue: Uncovering Developmental Diversity. Why did you decide to get involved?

My first two important papers were published in Development. Development is my favourite developmental biology journal. The request to be a Guest Editor was an honour for me. I hoped that I could use the position to support the plant comparative development, evolution and ecology communities.

What does your role as a Guest Editor entail?

The main role is handling manuscripts in a timely fashion and ensuring that they get good and honest reviews. But, I also hope that I can be a short-term ambassador for the journal in this diverse area. I hope that I might encourage people to consider sending their papers to Development. The other editors are stellar – I am fortunate to be part of that family for the year.

How do you see your research and the field developing in the next few years?

Firstly, for the field in general, I'm very excited about the development of new model systems in which we can ask developmental questions using emerging technologies to understand the molecular basis of morphological diversity.

I'm also very excited about using Marchantia to understand how meristems – the generative centres that generate plant bodies – develop and evolve. The multicellular haploid stage of the Marchantia life cycle develops from haploid spore produced by meiosis in isolation – separate from the parental plant. This makes it an experimentally tractable system in which to investigate how meristems develop de novo from populations of non-meristematic cells.

In your mind, do you have a definition for what you consider to be ‘diversity’?

It is what accounts for the morphological differences that we see in nature, and this can be within or between species. We can begin to understand the mechanisms that account for those differences at either hierarchy level. If we can understand how these mechanisms evolved, we gain an insight into how natural selection generates the diversity.

How important do you think an appreciation of developmental diversity is in the context of climate change?

When I present lectures to the public about the work we do, I highlight the role that plants play in the Earth system. Almost all life on the planet – with the exception of organisms in deep-sea vents and lithotrophs – depend on the radiative energy of the sun. Solar energy is transformed into chemical energy by photosynthesis. We cannot think about climate change, or the history of life on Earth, without understanding photosynthetic organisms – algae and plants.

Then there's the current context: how will climate change impact plants in the future? Here in Vienna, we're very lucky to live close to the Alps. The effects of climate heating is already stark. As the Earth heats, plants move to higher altitudes in the mountains; it's only a matter of time before they reach the summits. Where will they go then? The likelihood is some species will become extinct. Understanding the impacts of climate change and warming on plants is not only important for the maintenance of biodiversity and ecosystems upon which we, as humans, depend, but also for the whole Earth system, which depends on plants for its regulation. I'm keen to see how we can use our genetic approaches in Marchantia and our knowledge of how these plants grow to begin to contribute to understanding how plants respond to climate change.

Finally, what would Development readers be surprised to find out about you?

I teach an environmental science course to adults in Gaelic on the west coast of Ireland each summer. Gaelic is a threatened language and, just like threatened biodiversity, I feel it is important for us to conserve it and the cultural richness it provides for future generations. During the week-long course, we explore the ecological functions of plants in the local landscape. We then relate these local roles to the roles that plants play in global processes such as the carbon cycle and human wellbeing. Helping people see global ecological processes through the lens of local plants can give a tangible understanding of something as complex as the Earth system.

Liam Dolan's contact details: Gregor Mendel Institute, Dr Bohrgasse 3, Vienna 1010, Austria.

E-mail: [email protected]

Liam Dolan was interviewed by Alex Eve, Senior Editor at Development. This piece has been edited and condensed with approval from the interviewee.

Special Issue

This article is part of the Special Issue ‘Uncovering developmental diversity’, edited by Cassandra Extavour, Liam Dolan and Karen Sears. See related articles at https://journals.biologists.com/dev/issue/151/20.

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