Alison Bentley - Redomesticating wheat

Kat - Wheat is a hugely successful and important agricultural crop, originating from simple grass and grown in many parts of the world. But while its golden ears may seem as commonplace in the countryside as bread, pasta and other wheat products are in the kitchen, its genetics are very unusual. I spoke to Alison Bentley from NIAB - the National Institute of Agricultural Botany - in Cambridge to find out about the journey from grass to wheat, and how she's trying to recreate it.

Alison - So, the domestication and evolution of wheat started about 100,000 years ago in the Middle East when two grass species came together and created an intermediate wheat form and this later hybridised another time to produce what we know today as wheat and what we grow to produce bread and grain for animal feeds.

Kat - The wheat that we have today, that didn't just get there. it's been helped along the way by farmers going, "I like the look of that one, I like the look of that one."

Alison - Exactly. That plays a big role in it. So, these grasses are growing in fields in Turkey and areas in the Middle East and the early farmers were selecting the plants that had evolved through this coming together of multiple species and they were selected and moved forward and disseminated to different regions. That was really what drove this domestication and evolution of the wheat we know today.

Kat - Tell me a bit about the genetics of wheat. What's going on under the hood, because they are quite unusual the genetics of the wheat, the kind of wheat that are grown today in agriculture?

Alison - Yeah. I mean, when you drive past the wheat field, it just looks like a grass growing there. But underneath that is extremely complex genetics. So, it does still maintain the genomes of these three ancestral grass species which grew individually in fields in the Middle East. Those three genomes still exist and their huge genomes and they're very difficult to decode. So, we have a really big challenge in trying to understand the underlying genetics in wheat.

Kat - I heard they had about a hundred thousand genes something like that?

Alison - Something like that and there's a huge amount of repetitive DNA and all sorts of challenges in the way if you want to sequence any of that information.

Kat - In terms of the wheat crops that are grown maybe in Europe, in the US, in other parts around the world, how similar are they all?

Alison - So, they're fundamentally very similar. So, they vary just for a few adaptive characteristics that enable them to be grown across that range and that's really when wheat moved out of the Middle East. Those are the type of changes that allowed it to move out of those regions - so, into hotter, drier environments, to wetter, cooler environments. Those genes really play a big role in the spread and domestication of wheat throughout the world.

Kat - And then presumably, over the past couple of hundred years, as it became commercialised and farmed on a grander scale, fewer and fewer types got grown.

Alison - Exactly. So, a selective breeding has really narrowed that base so we're really making varieties then crossing those varieties to select new varieties. So, we're working on quite a small base of genetic diversity.

Kat - Tell me about the work that you're doing then to try and increase the genetic diversity in wheat.

Alison - So, that's exactly what we're trying to do. We're saying, this genetic basis is very low and that's a limitation to our ability to improve wheat in the future. We need to do that because the levels of yields are plateauing all throughout Europe. So, what we're doing is going back to the Middle East, collecting a wide range of accessions of the original grass species saying, "Can we recreate wheat as it was created in nature all those years ago? Can we do that?" by doing that, introduce new diversity that we can then exploit in breeding.

Kat - So, the grasses that are growing now, they've had thousands of years to accumulate new traits or maybe just combine in new and more interesting ways.

Alison - Exactly and I think the original hybridisation events of these are initial events that created wheat occurred in quite a small region whereas these grasses occur over really wide geographic range. So, you've got the Tibetan plateau, you've got inner Mongolia. So, lots of different environments. So, you can imagine in each of those regions, they've evolved to different circumstances, different nutrient availabilities, different temperature and climate. So, it's a really rich source of diversity for us to use.

Kat - One of the hot topics it's hard to avoid in science is climate change. In a lot of places where crops are grown, they may be getting drier or saltier. Do you hope that these new kind of reconstructed wheats might be better equipped to cope with these challenges?

Alison - Yeah, exactly and that's what we see whenever we look at these grass species and the material we derive from them. So, we have lines that perform, maintain their yield at lower input level so you can apply the same or lower amounts of inputs and that's a really topical thing in agriculture. You can apply less nitrogen and hold the yield. So, these are bringing in really new exciting diversity for those kind of traits which are very topical.

Kat - So, less fertiliser basically.

Alison - Exactly. So, if you could maintain the yields - so, even if you could only maintain current yields but apply half the nitrogen, that would represent a significant cost and environmental saving. So in this case, if we can do that and increase the yields then that's really - we're on a winner with that.

Kat - It's a lovely picture to think of you and your colleagues collecting these grass around the Middle East and crossing them in your lab. How do you turn that into the amount of seed you'd need to fill an entire field or whole country's fields?

Alison - Yes. So, there's definitely that issue of scaling and the time it takes to do that in wheat. So, we have what we call a pre-breeding pipeline where we move the material through from those initial crosses in the glasshouse, doing all that really fine scale work. and then we have the ability to scale that up fairly quickly to a material which we can disseminate to other people and that they can grow and assess as well.

Kat - In a recent podcast, we had a discussion about intellectual property, particularly around crops and agriculture and whether there should be patents and these kind of things on crops. Are there strains that you're coming up with the kind of things that could be patented, that companies could still control?

Alison - Not really. So, there's a treaty governing the use of wild relatives and they belong essentially to the country in which they were collected and they can't be directly commercialised on. The project that we work on funded by BBSRC, in that project, all the material we create is completely IP free. So, none of the data, none of the material is held or owned by anyone. So, we're freely distributing that material, really with the view that it can be used to improve UK wheat and wheat more widely. So, it's really what we call public good plant breeding. So, we are producing resources that are then freely available for people to use.

Kat - NIAB's Alison Bentley there.