This year’s wheat harvest is currently underway across the country after a difficult growing season, with harvest itself being delayed due to intermittent stormy weather. The high levels of rainfall at the start of the growing season meant that less winter wheat could be planted and dry weather in April and May caused difficulties for spring wheat as well. This decline in the wheat growing area has caused many news outlets to proclaim the worst wheat harvest in 40 years and potential bread price rises.
Difficult weather during this year’s growing season. Photo: Joe Oddy
This is also the first wheat harvest in which I have a more personal stake, namely the first field trial of my PhD project; looking at how asparagine levels are controlled in wheat. It seemed like a bad omen that my first field trial should coincide with such a poor year for wheat farming, but it is also an opportunity to look at how environmental stress is likely to influence the nutritional quality of wheat, particularly in relation to asparagine.
The levels of asparagine, a nitrogen-rich amino acid, in wheat grain have become an important quality parameter in recent years because it is the major determinant and precursor of acrylamide, a processing contaminant that forms during certain cooking processes. The carcinogenic risk associated with dietary acrylamide intake has sparked attempts to reduce consumption as much as possible, and reducing asparagine levels in wheat is a promising way of achieving part of this goal.
Asparagus, from which asparagine was first discovered and named.
Previous work on this issue has shown that some types of plant stress, such as sulphur deficiency, disease, and drought, increase asparagine levels in wheat, so managing these stresses with sufficient nutrient supply, disease control, and irrigation can help to prevent unwanted asparagine accumulation. Stress can be difficult to prevent even with such crop management strategies though, especially with environmental variables as uncontrollable as the weather, so it is tempting to speculate that the difficulties experienced this growing season will be reflected in higher asparagine levels; but we will have to wait and see.
Plant breeders are increasingly using techniques to produce new varieties they say are indistinguishable from those developed through traditional breeding methods. New genome editing technologies can introduce new traits more quickly and precisely.
However, in July, 2018, the European Court of Justice decreed they alter the genetic material of an organism in a way that does not occur naturally, so they should fall under the GMO Directive. This went against the opinion of the Advocate General.
In October 2018, leading scientists representing 85 European research institutions endorsed a position paper warning that the ruling could lead to a de facto ban of innovative crop breeding.
The paper argues for an urgent review of European legislation, and, in the short term, for crops with small DNA adaptations obtained through genome editing to fall under the regulations for classically bred varieties.
‘As European leaders in the field of plant sciences […] we are hindered by an outdated regulatory framework that is not in line with recent scientific evidence,’ says one of the signatories, Dirk Inzé, Scientific Director at Life Sciences Institute VIB in Belgium.
A new type of wheat, chock full of healthy fibre, has been launched by an international team of plant geneticists. The first crop of this super wheat was recently harvested on farms in Idaho, Oregon, and Washington state in the US, ready for testing by various food companies.
Food products are expected to hit the US market in 2019. They will be marketed for their high content of ‘resistant starch’, known to improve digestive health, be protective against the genetic damage that precedes bowel cancer, and help protect against Type 2 diabetes.
How do carbohydrates impact your health? Video: TED-Ed
‘The wheat plant and the grain look like any other wheat. The main difference is the grain composition: the GM Arista wheat contains more than ten times the level of resistant starch and three to four times the level of total dietary fibre, so it is much better for your health, compared with regular wheat,’ says Ahmed Regina, plant scientist at Australian science agency CSIRO.
Starch is made up of two types of polymers of glucose – amylopectin and amylose. Amylopectin, the main starch type in cereals, is easily digested because it has a highly branched chemical structure, whereas amylose has a mainly linear structure and is more resistant.
Bread and potatoes are foods also high in starch. Image: Pixabay
Breeders drastically reduced easily digested amylopectin starch by downregulating the activity of two enzymes, so increasing the amount of amylose in the grain from 20 to 30% to an impressive 85%.
The non-GM breeding approach works because the building blocks for both amylopectin and amylose starch synthesis are the same. With the enzymes involved in making amylopectin not working, more blocks are then available for amylose synthesis.
‘Resistant starch is starch that is not digested and reaches the large intestines where it can be fermented by bacteria. Usually amylose is what is resistant to digestion,’ comments Mike Keenan, food and nutrition scientist at Louisiana State University, US. ‘Most people consume far too little fibre, so consuming products higher in resistant starch would be beneficial.’
He notes that fermentation of starch in the gut causes the production of short-chain fatty acids such as butyrate that ‘have effects throughout the body, even the mental health of humans’.
The GM wheat will hit US supermarkets in 2019. Image: Pxhere
The super-fibre wheat stems from a collaboration begun in 2006 between French firm Limagrain Céréales Ingrédients, Australian science agency CSIRO, and the Grains Research and Development Corporation, an Australian government agency.
This resulted in a spin out company, Arista Cereal Technologies. After the US, Arista reports that the next markets will be in Australia and Japan.
Cassie Sims is a PhD researcher at Rothamsted Research in Harpenden, UK. Photo: Rothamsted
Rothamsted Research is the oldest agricultural research station in the world – we even have a Guinness World Record for the longest running continuous experiment! Established in 1843, next year we celebrate our 175th anniversary, and as a Chemistry PhD student at the institute today, I can’t wait to celebrate.
Wheat samples from the record-breaking Broadbalk experiment. Photo: Cassie Sims
Rothamsted is known for many amazing scientific accomplishments, and it has a rich history, which I have explored through many of the exhibitions put on by the institute for the staff every month or so.
One of the old labs set up for the exhibitions we hold at Rothamsted. Photo: Cassie Sims
Working in what was the Biological Chemistry department, I am following in the footsteps of Chemists such as Michael Elliott, who developed a group of insecticides known as pyrethroids. These are one of the most prolific insecticides used in the world, still widely used today and researched here at Rothamsted – in particular, the now-prevalent insecticidal resistance to them.
I was privileged to view an exhibit of Michael Elliott’s medals late last year at Rothamsted – one of the opportunities we are given as staff here. Recently, I was also able to view a collection of calculators and computers from the earliest mechanical ones, to Sir Ronald Fisher’s very own ‘Millionaire’ Calculator, which could multiply, add and subtract entirely mechanically.
Sir Ronald Fisher’s ‘Millionaire’ Calculator. Photo: Cassie Sims
In more recent times, Rothamsted has had an update (a little more than a lick of paint) with newer buildings, labs and equipment constantly being added. My office and lab are situated in the architecturally interesting Centenary building, which was built only 10 years ago. Some of the research has had an update too – plant science research is a bit more focused on molecular biology these days, and our chemistry has been significantly advanced over the last century by advances in analytical equipment.
A few years ago, Rothamsted was briefly the centre of media attention due to a ‘controversial’ GM field trial testing wheat made to emit (E)-β-farnesene, the aphid alarm pheromone, and whether the plants could repel aphids.
…they couldn’t, but this was one of the first type of GM trials of its type, and it was an interesting study that combined many disciplines of science, from molecular biology and plant science, to entomology and chemical ecology.
Rothamsted is not just about science, either – we have a few longstanding social traditions such as Hallowe’en parties and Harvest Festival, not forgetting of course my favourite; our summer Sports Day, which provides much entertainment in the form of serious research scientists participating in sack races to win some outstandingly tacky trophies. We also have an onsite bar (if that is what you could call it), which is a little more like a converted cricket club, and serves as a venue for most events, and has been the location of many of my great memories.
If I had to describe being a student at Rothamsted in one word, it would be weird! There is a lot of fun to be had, but we are also surrounded by an incredible history that we cannot forget as we forge a new path in our fields (literally and scientifically!).
I hope one day that I can leave some kind of mark here – but even if not, I will be happy to have been part of such a prestigious institute and to have worked alongside such great scientific minds.
What are the sustainability challenges being tackled by researchers at Rothamsted? Sir John Beddington, Chair of the Rothamsted Research Board gave this talk at SCI in London in September – part of our ongoing programme of free-to-attend public evening lectures.