Science Interviews


Tue, 15th Mar 2016

Can you turbocharge your porridge?

Professor Howard Griffiths, The University of Cambridge

Listen Now    Download as mp3 from the show Cambridge Science Festival: Battle of the Brains

Food security is a pressing issue, our population is rising whilst climate change is Figure 6: Wheat is used in a wide range of foodsbattering our agriculture. On top of that wheat, one of our staple crops has hit a brick wall in yield increase - is it time to get turbo charging? Howard Griffiths thinks so, as he displayed something that looked suspiciously like the contents of a cornfield to Chris Smith...

Howard - Well, it is the contents of a corn field and what I’d like to do is hand out some of these to some of these youngsters here…

Smith - What are you dishing out?

Howard - Well I’m giving out some ears of wheat that I collected from a field and it illustrates… How many of you like toast for breakfast?

Audience - Yes!

Howard - Excellent.  Well wheat is a staple product of the world; it feeds and it gives us a huge amount of protein. The ears that I’m holding up in front of you contain little grains and those little grains - you can pull them apart and have a look - those are the seeds of the wheat and having sown one of those seeds in the autumn, the farmer was then able to grow all these ears of wheat.  Well these are the ones that are left behind that he didn’t quite manage to harvest.

Smith - What proportion of the world relies on this simple stuff - this cereal crop?

Howard - A huge proportion of the world relies on this as a staple diet.  It’s one of the major protein inputs because it’s go so much nitrogen in it but there is a problem with it because, over the last 10 or 15 years or so, the yields from wheat have begun to plateau.  They’ve reached a stable level; they’re not increasing as much as they used to do over the previous 30 years since the green revolution.

Smith - Why is that a problem?

Howard - Well, that’s a bit of a problem because the world’s population is increasing and also we’re likely to get a change in climate in the future which will mean, increasingly, crops won’t be as productive as they have been in the past.

Smith - You’re saying then we could be facing a hungry future?

Howard - Yes indeed. I mean there are other issues that we need to tackle; not just about increasing the productivity of the wheat, we’ve got to minimise waste. For instance, these ears I’ve picked up, the farmer hadn’t managed to harvest them and all around the world there’s a huge amount of food waste that we need to try and minimise…

Smith - So you stole that?

Howard - Well - I helped myself.  I liberated it, that's the word we tend to use. Also, of course, we’ve got to improve our distribution of these sorts of foodstuffs so that it helps people who don’t have food but also doesn’t destroy their economy by distributing it in a way that would upset the national product of a particular country.

Smith - So we have a situation where yields of this very important food crop are not going up.  The human population is going up; we also anticipate that the environment's going to change because of things like climate change so that may also dent the yield.  So what’s your solution?

Howard - Well there are other sorts of plants.  How many of you like cornflakes?

Smith - I’d say Kellog’s are not doing very well in this room.  There's only about two or three hands up..

Howard - There are other versions of cornflakes available from your local supermarket - you do realise?  So, cornflakes are made from maize corncob - do you all know what a corncob looks like?  Each one of those little granules on a corn cob, that’s where your cornflakes come from.  Now they come from of a plant that actually have a higher rate of productivity and they’re what we call turbocharged, so naturally this is a plant that has managed to increase its productivity by force feeding the enzyme that fixes carbon from the atmosphere.

Smith - This energy that comes to us from wheat, we get effectively from the sun don’t we?  Because this plant captures the energy from the sun through the process of photosynthesis and it stores it chemically in a form that we can then eat?

Howard - Absolutely.  Plants are magnificent; when you think they take that amazing energy we get from sunlight for free and they turn it into the products that feed us, they clothe us…  How many of you are wearing cotton at the moment?  And they also fuel us.  If you came in a car, that’s fuel that was laid down by plants millions ,and millions, and millions of years ago.

Smith - How can we therefore, make that plant better at being a natural solar panel then?

Howard - Well, one way would be to take that pathway that we get in sweetcorn and maize and encourage staple crops like wheat or rice to see if we could adopt that pathway into them as well.

Smith - Right.  So basically, take what the maize is really good at and confer that same science on the wheat?  Why doesn’t the wheat do that already?

Howard - It hasn’t had to because it evolved in a wet and cool environment, whereas maize comes from a tropical environment where it's hot and often water limited, so that’s the advantage of that crop as well as having this turbocharger.

Smith - How can you put this turbocharger, as you put it, into the wheat?  Is that feasible?

Howard - That is a real problem because it means that we would have to find wheat that had a slightly different structure within their leaves which would allow us to put that pathway in.  We have an alternative solution and that alternative solution… You can see here I’m holding up a vial of green cells…

Smith - I thought it was a urine specimen.  It’s in one of those pots the doctor give you Howard.

Howard - Chris - if your urine has got that colour I think you do need to see a doctor.

Smith - I did have a patient with that once and he was on a certain drug that made his wee go green.  But why does it look green then - what’s in that pot?

Howard - This has got a microscopic algae in it; it actually grows in soil and solutions.  Many of you have buckets in your gardens that have been gathering water all over the winter , I bet they’ve gone a bit green haven’t they - yes?  So that algae is all very close relatives of it.  Other sorts of things grow in ponds and in buckets and in soil.

Smith - And they’re plants are they?

Howard - They are plants indeed.  Well, they’re related to plants and they also have a mechanism which turbocharges their photosynthesis and they do it in every single cell.  So what we are wondering is, they have a much simpler mechanisms for concentrating that carbon dioxide and improving the efficiency of the enzyme, could we try to persuade all the cells in a plant like wheat.  If they could adopt that mechanism,maybe that would improve their photosynthesis and that would help us increase that yield of wheat, and rice, and so on by 10 or 20%, which is what we will need to do over the next 50 to 100 years

Smith - You’re saying, take the machinery from the stuff that makes the pots in your garden go green and put that into wheat, and it would like putting a Porsche engine into a Lada?

Howard - Indeed, that is the sort of idea - yes.  I hadn’t quite thought of it like that.

Smith - But is it feasible?

Howard - It is feasible.  We have actually managed to get parts - little microscopic components that help to pump the carbon inside the cell walls of the algae to work inside plants.

Smith - And if you do this, what sort of increase in productivity of normal wheat might we be able to see?

Howard - Well, we would hope to see a 15% increase in wheat yield, I would imagine would be the sort of thing that would maintain that stability for the future.  In the short term, of course, we’re going to rely on traditional genetics, traditional breeding that will help to bring in new traits and help to maintain pathogen resistance but, in the future, perhaps we could get away with this mechanism.



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