GM wheat research in full flow

Applying Nitrogen to Spring cereals? After several years of being the forgotten crop in the global development of genetically modified crops, wheat is suddenly smack bang in the middle of most biotech programmes.

It was 2004 when Monsanto decided to plug on Roundup Ready wheat, with media reports at the time citing a lack of consumer acceptance as a key reason. A number of important export destinations for North American wheat were not keen on buying GM wheat, while even growers, through North American wheat associations, were lobbying against its introduction, fearing there would be no market for their grain.

But in 2009 that all changed, with a joint announcement from nine Canadian, American and Australian wheat organisations that they would work towards the synchronised commercialisation of biotech traits in wheat crops, opening the door for both commercial organisations and research institutes to start developing GM wheat.

That change of heart was prompted by an acknowledgement that a lack of investment in wheat research had left development behind that of competing commodity crops.

In America, in particular, wheat production has come under pressure as advancements in maize and soya, partly through biotechnology have helped those crops achieve higher productivity gains than in wheat.

The increased profits generated by those crops have understandably caused growers to switch away from wheat and into other crops where they have alternatives. And with drought tolerance in maize moving towards commercialisation in the USA, there is an increasing prospect of a continued decline in wheat production.

Those issues, and that the longer wheat continued down a non-GM path, the more likely the gap between wheat yield growth and other commodity crop growth would increase, led to the joint statement from the wheat growers associations and a flurry of activity in both commercial and research worlds.

Monsanto, for example, reacted by acquiring Montana-based breeding company WestBred in 2009 to add wheat to its seed and traits business, and later formed a strategic alliance with BASF. Similarly, Bayer CropScience has recently announced an alliance with seed breeder RAGT, and formed research agreements with institutes, such as CSIRO in Australia and Evogene in Israel.

Unlike the first incarnation of GM wheat, which was all about herbicide tolerance, the traits of interest in most of these programmes are second generation technologies, such as drought resistance and helping to improve nitrogen use efficiency

The latter is already being investigated in field trials in Australia as part of the CSIRO Food Futures National Research Flagship programme with the aim of reducing the amount of nitrogen applied to the crop without compromising yield, says Bruce Lee, director of food futures programme at CSIRO.

Another line being trialled has significantly increased yield in laboratory tests.

But the most controversial lines being researched by CSIRO are ones where there is an effort to produce grains with in-built health attributes

For example, one line has had a single gene switched off leading to a different composition of starch in the grain. Starch is an important nutrient for humans and digested in the small intestine, with the resulting glucose absorbed and used for energy.

But a component of the starch escapes digestion and enters the colon, where it broken down by the resident bacteria releasing short chain fatty acids. These are a source of energy for the large bowel wall and are important in bowel health.

The GM lines will increase the amount of this resistant starch in the grain by boosting the amylose content from 25% to 70%, explains Dr Lee. "We hope that diets which contain this high amylose wheat may help to reduce the incidence of colorectal cancer."

Most Australians, according to CSIRO, only consume 10-20% of the recommended daily intake of resistant starch, which could contribute to the high rates of diet related diseases, such as diabetes and colorectal cancer in the country.

Colorectal cancer kills 4,400 Australians every year, while Type 2 diabetes affects 8% of the population.

Another line will investigate whether grains with altered carbohydrate profile are digested more slowly in the small intestine, and therefore whether the conversion of starch to glucose is reduced. That could reduce the glycaemic response during digestion meaning less insulin is needed to control blood glucose levels.

One of the aims of the trials is produce enough grain to conduct animal and potentially human feeding trials eventually to confirm the health benefits of these grains.

Feeding trials would follow a strict and established protocol involving rats initially to determine the effects of the grains on indicators of bowel health or blood glucose levels. If successful, studies would move on to pigs, which are closer to humans in gut physiology and consume similar quantities of food.

It is that possibility that prompted Greenpeace to destroy around 0.5ha of GM wheat trials in July, using many familiar arguments in its justification, including calling into question its safety.

That action suggests that while research institutes and the breeding companies are keen for GM technology to be introduced into wheat, there is a still a way to go to for consumers to be won over.

UK GM wheat field trial

The first small scale field trial of GM wheat in the UK could take place if DEFRA approves Rothamsted Research’s application to test whether its GM wheat plant are resistant to aphid attack.

The institute has used a gene gun to insert a gene from peppermint plants that makes a substance called E-beta-farnesene (EBF), an aphid alarm pheromone that occurs naturally in over 300 varieties of plants.

"In the lab we have demonstrated the GM wheat plants repel aphids and attract parasitoids and predators that naturally control the number of aphids in the environment," explains Toby Bruce, a principal investigator in Rothamsted’s chemical ecology group.

"The trial will investigate whether the GM plants work outside in the field as well as they do in the lab."

In addition, to the main gene being tested, a second one that will boost the production of the aphid alarm pheromone will be tested in combination with the peppermint gene, he adds.

Summer aphids rather than those that cause barley yellow dwarf virus infections in the autumn are the target. "We aim to find out whether aphid infestations are lower in the summer on the transformed plants than untransformed wheat. If the trait works as intended, the GM wheat would substantially reduce the need for aphicide treatments."

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