June 19, 2019, by Lexi Earl

Meet the Beacon: Prof David Salt

Professor David E. Salt is the Director of the University of Nottingham’s multimillion pound Future Food Beacon of Excellence. Prof Salt left the UK after his PhD in 1990 to work as an academic in the US where he became a Full Professor at Purdue University in 2005, and where, from 2004 – 2007, he was the Scientific Director for Genomic Research and Technology for the Bindley Bioscience Centre. In 2011 he came back to the UK as a Chair in Plant Science, and the founder and co-Director of the Centre for Genome-Enabled Biology and Medicine at the University of Aberdeen. In Aug 2016 Prof Salt took up a new Chair in Genome-Enabled Biology at the University of Nottingham.

In this interview, David talks to Lexi Earl about his research career, provides his advice for young scientists, and explains the origins of the Future Food Beacon.

Tell me about your career, how did things begin and evolve?

I’ve been working on this science for a long time. I’ve always been interested in how plants adapt to their environments. I did my undergraduate degree in Biochemistry but then I did a Masters in Computer Science, because I decided computers were going to be important (this was the early 1980s). I was really interested in modelling. Because I’d had government funding to support my Masters, I was not eligible for further government funding for a PhD, so I was limited to PhDs that were funded through other mechanisms. There was a PhD at the University of Liverpool, funded by The Royal Society, working on copper tolerance in Mimulus guttatus, the yellow monkey flower.  At the time, I was in Sheffield doing my Masters, I was into clubbing and the scene in Liverpool was fantastic so I ended up there doing a PhD. After my PhD, I decided I wanted to go to London so I did a postdoc at University College in biochemical engineering. I was studying the large-scale purification of proteins. It was completely different to what I had done my PhD on, but it was interesting and a fun place to be. This is when I discovered the ‘world music’ nightclub at Ronnie Scott’s Jazz Club just down the road from my favourite coffee shop in London ‘Bar Italia’ in Soho.

David, against a hill, with a trowel in hand, collecting field samples of plants

Science in the field – collecting field samples of Thlaspi goesingense at a serpentine site in Austria.

Once that postdoc was finished, I was keen to work abroad. After some investigating I found several key people working in the area of metals in plants that were based in the US. I wrote to a few of them, asking if I could join their labs as a postdoc. I wrote to George Wagner, who was based at the University of Lexington, in Kentucky, and he had funding for a two-year post so I packed up everything, took my small suitcase and guitar, and left for Kentucky. I can still remember getting off the plane for the first time – the temperature, the cicadas, the humidity. It was a new world.

David and two others play guitars around a bonfire

Early ‘lab meetings’ in Indiana with son Liam, Tommy Sors, and Tom Leustek

I worked on how cadmium is transported across plant membranes, and made some seminal discoveries during that postdoc. I published a paper in the Journal of Biological Chemistry (JBC) that has led to a lot of molecular work since then. I met my wife, Karen there too. After two years, I still didn’t want to come back to the UK, and so I wrote to Wilfred Rauser, who I knew through the literature, who was at the University of Guelph in Canada. He had done a lot of work on compounds called phytochelatins, which I was involved in discovering during my PhD, and which are involved in binding metals in plants, as part of the detoxification mechanism. We knew from work that George Wagner had done while I was in his lab that the peptides that bind the metals seem to accumulate in the vacuole in plant cells. We did not know how the peptides got into the vacuoles, so I proposed to go to Wilfred Rauser’s  lab to study that transport process. We were in Guelph for two years. Our twin boys were born there. Once that postdoc was finished, I decided it was time to move on from being a postdoc and I was lucky enough to get a position at the University of Rutgers, as a Research Assistant Professor. That was a five-year, fixed term position. I was at Assistant Prof level, but I just did research. I was able to get my first two big grants while I was at Rutgers, initially from the USDA, and then the US Department of Energy – I have been continuously funded ever since. One grant was to continue work on the transport of phytochelatins , and the other was to work on a project examining a small molecule that binds nickel in special plants that hyper accumulate metals such as nickel and zinc. I published papers on that research, and had my first postdoc there, Ute Kramer, who has gone on to be a successful scientist. Since that first post I have had 29 postdocs in my lab, many of  whom now have their own labs in the US, China and Japan, or are working in industry. Being at Rutgers  was an interesting experience. I learnt how to run my own lab, write my own grants, figure out what it means to be an independent scientist.

David and colleague holding plant samples from an urban garden site

David, right, with Mike Blaylock, at the Trenton urban garden site

Because that was a fixed-term position, I then began to look for a tenure-track post. I was lucky enough to get a position at the University of Arizona in Flagstaff. That was my first experience trying to run a group and teach. I was based in the Chemistry department, as an Assistant Professor of Chemistry. That was quite interesting because my first teaching assignment was to teach intro chemistry to freshmen (first years) and I hadn’t done Chemistry since my A-levels! I also taught two levels of biochemistry. That was tough. I was teaching full-time, writing grants, trying to keep my lab going. I met Mary Lou Guerinot, who became a long-term mentor, who is based at Dartmouth College in New Hampshire, US. We wrote a grant together with Julian Schroder, Jeff Harper and John Ward for the US National Science Foundation (NSF). They have a programme called the Plant Genome Programme. We put together a project on ionomics in 2000. We were successful on our second attempt and the grant was worth around $8million. I got tenure at Flagstaff. I then applied for a position at Purdue University. They had an opening for an Associate Professor and I was able to get a permanent position at Purdue. We moved to Indiana in 1999/2000, and that is where we had our daughter. I was at Purdue for 11 years. I started to build my lab and my reputation. I won more grants from the NSF. I branched into natural variation and looking at the molecular mechanisms that underpin natural variation in the ionome. In some sense, that was me getting back to my PhD work. I was able to get funding from the US National Institute for Health (NIH), which was quite unusual because they only rarely fund plant people. That grant allowed me to grow my research area in natural variation. I got great postdocs, including Ivan Baxter who leads his own group now at the Donald Danforth Centre, St Louis, and Daiyin Chao, we published a paper in Science and he is a now a Professor at the Shanghai Institute of Plant Physiology and Ecology.

Two men, Fangjie Zhao and David Salt, in a glass house full of plants

With longtime collaborator Fangjie Zhao

By 2010, Karen had finished her PhD and was looking for her next step. She was offered an Assistant Professor’s position at Purdue but we felt that for Karen’s career it would be better if she went somewhere else. It is never really a good idea to stay at the same institution. After 20 years in the US, I decided I wanted to come back to the UK. I can’t explain why exactly. My two boys were at university at that point, and one was back in the UK already, and our daughter was in high school. In 2008 I had been over at a meeting in Aberdeen, on arsenic accumulation in rice. I thought it was an amazing city. When we started to think about coming back to the UK, we were dealing with what is called the ‘twin body’ problem – you have two academics and you are looking for a university that will give you both positions – so that narrowed things down a little. I wanted to build the Centre for Genome Enabled Biology, an idea I had been developing for a while. I wanted to do something bigger than just my own science. I wanted to take hold of this emerging field where people are using genomics and the associated methodologies to ask questions across disciplines. I thought we needed to create a platform to allow us to do genome enabled biology and that would allow us to be leaders in many different areas. We moved to the University of Aberdeen and we were there for five years. I was able to established the Centre for Genome Enabled Biology & Medicine at Aberdeen, and it is still there are going strong. After five years at Aberdeen opportunities came up at UoN so we decided to move to Nottingham. Karen started in May and I started in August 2016.

Tell me about the origins of the Future Food Beacon?

I am still really interested in genome enabled biology – the bioinformatics, the sequencing, the phenomics, everything together in a pipeline. Prof Malcolm Bennett is also interested in this concept. We initially put in a Beacon around that concept, called genome to phenome. It was about trying to understand the connections between the genome and the organism, how the genome is translated into the organism. We justified the project ideas through the concept of food security but it was more about the fundamental science behind getting new crops, and eventually using the same platform for livestock. At the same time, Prof Tim Foster was putting in a Beacon bid strongly focused on the food side.. We submitted separately and as part of the review process, the reviewers suggested that we fuse the two ideas. I talked to Tim about bringing the two projects together, and I was really eager to lead the Beacon, which fortunately Tim was okay with. I am now totally becoming immersed in the whole food side of things. Once I started to think about how I wanted the Beacon to work, I realised I wanted it to be an open platform for research. I realised that we needed to be enabling research across the whole food system, including Social Science and Arts and Humanities.

What are the aims for the Future Food Beacon?

I think there are two arms to this really. There are the rigid deliverables that the Beacon has. The University is investing £16 million in the Beacon, and they want to recoup that so they are expecting the investment will raise success in terms of getting external grant funding. It’ll raise our ability to publish higher quality papers and it will increase our international standing. People will look at UoN and think wow, they’re doing amazing work in this area – they’re publishing all these papers, giving great talks, producing great students and postdocs. We have very clear targets that you can put a number on. Outside of that, I am also hoping that we can really have an impact on the food system in terms of food security, nutritional security. It is a massive and daunting problem. In terms of grants success and getting external funding, a lot of that is about telling a convincing story. Refining the narrative is the first thing you need to do and then you can start to use the narrative in different places to generate funding, interest and buy-in to the project. To develop a good narrative about something you need to identify a topic for your story. If you can do that, that gives you a nice place you can have significant impacts. Those stories can be different. The stories that we are building around food deserts is one such example. It is an intriguing term, there is good content, it is easy to engage people. But it is also a space where we can have an impact. We also have a cocoa project with this potential. Once you start affecting people’s lives, it becomes a talking point.

Another outcome which is perhaps subtler is this idea of it being a disruptive mechanism. The University knows it wants to improve but it is an incredibly complex institution. To make anything happen at the university, on the systems level, is almost impossible. It is easy to make things happen at an individual level, because it is fairly chaotic. If you have resources to invest in something, and you give the money to existing mechanisms, what is most likely to happen is more of what is already happening. It isn’t necessarily going to change anything. The Beacons are, in a positive sense, disruptive. They sit outside the traditional systems – these are not bounded by a single  school or faculty, but rather they intersect multiple organisational units. They can influence people. Stuff is going to happen. Through that disruption, we may be able to make some permanent change for the better.

David Salt, in beret, with the sea behind

David during his sabbatical in Tuscany

What is the importance of the Beacon for ordinary people?

Cocoa is a clear example of research impacting ordinary people. We have just got back   from Colombia. While we were there we worked with female smallholder cocoa growers, trying  to help them improve the quality of the beans and enabling them to sell their cocoa beans to premium chocolate makers in Nottingham. They get more for their beans, and this in turn helps improve their families’ livelihoods. So, there is a direct impact. Stories like that have a lot of content, a good narrative, and they impact directly on a person. We are always looking for stories like that. There are other projects that are maybe more inspirational, so people can look to see what we are doing and become inspired. We need to learn how to communicate that. We have a project in Senegal on pearl millet that is focused on capacity building to improve both the crop and its uses, so that people in Senegal directly benefit.

We are also very focused on community outreach and engagement. That will have a big influence individually. Plus we are working with small businesses, working together to help improve various companies, and that will impact on people too. There is a balance to be struck between good science, supporting businesses, and connecting with people.

The ionomics of grapes – research conducted in Tuscany by Prof Salt

Do you have any advice for young scientists?

You need to figure out what your story is. It sounds simple, but what is your story? When you start out, you’re thinking about an experiment, always. And you need to end up thinking about a programme. In order to sell your programme, you have to be able to wrap a narrative around it. It becomes what is unique about you. You have to have enough focus so you can put in targeted grants but it has to be flexible enough to allow you to play in a broad space. For example, I work on ionomics, so I can publish papers on complicated genome-wide association mapping in Arabidopsis, looking at arsenic accumulation in rice… I can work on cadmium accumulation in cocoa and get funding from Mars. It is all the same story. I can sell that story to all those different people because I have a unifying narrative. Getting that is really important. You also need to figure out what problem you are going to study and that problem needs to have societal significance.

Landscape of vineyards with mountains behind

Tuscan vineyard which was the location for Prof Salt’s sabbatical

Do you have a greatest career moment?

It is a series of events. When I decided I was going to move from the US, I was really interested in taking a sabbatical. You get a sabbatical every seven years in the US, and I hadn’t had one, and so I was long overdue. I had met Luca Maroni, who was a head winemaker in a vineyard in Italy and I wanted to do my sabbatical there so I came up with this crazy idea to do ionomics on grapes, while I was working in the vineyard for three months, over the harvest period. While I was doing that project, I was awarded one of the highest research awards at Purdue – the McCoy Award. I went back to the US to give my acceptance address and as part of my talk, I spoke about my research in the vineyard and how I was looking at the effects of the terroiron the ionomics of the grapes. The President of the university thought it was fantastic. It summed up for me the scientist’s life. You can be doing the coolest stuff, on all kinds of levels, but you need to be bold! That is one high point but there have been many!

Photograph of David Salt in a suit, giving a speech

Prof Salt speaking at his acceptance of the McCoy Award at Purdue University

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