Aim: Resistant barley with improved malting and fodder qualities
Up until now genetically modified barley has received little attention in Europe. Most of the research and development has been conducted in the USA, where the prime crop-breeding objectives are to improve the processing qualities of barley both as an animal feed and as a raw material for the brewing industry. Research is also being conducted to increase the resistance to harmful fungi. Safety research is currently focusing on two genetically modified barley lines.
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Barley is one of the oldest crops and probably the oldest cereal grown by a man. Today barley is used in many regions throughout the world thanks to its great ability to adapt even to unfavourable growing conditions. It is one of the most important cereal types after maize, rice and wheat. In 2005, 154 million tons of barley were harvested worldwide, more than half in the countries of the European Union. The main producers are Russia, the Ukraine and Canada. Germany lies in fourth position producing almost 11 million tons. Barley is mainly grown as animal feed. Special barley strains with high starch content are used as brewer's barley in beer making. |
Barley is used for human consumption in the form of pearl barley and semolina, in muesli and occasionally also as flour. It can also be used to make malt coffee.
Barley is also used as a renewable raw material for bioethanol production.
Main area of research: improved malting and fodder qualities
Barley plays only a minor role in the development of genetically modified cereals, since most research focuses on wheat. All genetically modified barley lines today are still at the development stage, none have yet been grown commercially.
Most research and development takes place in the USA. One main focus of the research is to improve the fodder and brewing qualities of the barley. To optimise fodder quality, genes from bacteria which produce the enzyme glucanase are transferred to the barley. This enzyme helps to break down the glucan in the barley grains, an important structural component of the cell walls. The barley can then be fed to animals, which lack the enzymes needed to break down the long chain glucans present in the barley cell walls. Poultry fed on barley usually remain small and have "sticky" droppings. In poultry trials it was shown that the birds were better able to digest barley containing an admixture of just 0.02 percent genetically modified barley.
The same approach transferring glucanase genes to break down glucan is also used to improve the brewing characteristics of barley. By transferring a gene from the commonly occurring soil bacterium Bacillus amyloliquefaciens, barley strains which produce heat-resistant glucanases have been developed. The enhanced processability of the barley achieved by breaking down the glucans also reduces manufacturing costs in the brewing industry, since filters no longer become blocked with glucans.
In the USA there have been 53 deliberate releases of transgenic barley since 1993, most of them in the last five years. By contrast, in Europe there have been only five field trials with barley to date. At the beginning of April 2006 the release of genetically modified barley was approved in Germany for the first time. This barley is currently the subject of two ongoing biological safety research projects.
Fungus-resistant barley - the focus of safety research
Fungal infections, in particular fusarium fungi, are a frequent problem in cereal cultivation. Some fusarium species produce fungal toxins (mycotoxins ), which mix in with the harvest and can cause serious problems in animal feed and also in the brewing industry. Barley, however, is less susceptible than wheat, oats and even maize.
Two safety research projects are currently studying genetically modified barley with increased fungal resistance. The barley strains involved in the project were developed at Washington State University and have already been tested in the field.
Two barley strains are under investigation. One of the strains contains a gene from a soil fungus (Trichoderma harzianum), which produces a chitinase. Chitinases break down chitin, which is also a component of fungal cell walls.
The other strain contains a gene from a soil bacterium (Bacillus amyloliquefaciens), which produces glucanase. The gene was transferred to barley to improve both its brewing qualities and its digestibility when used as fodder. But glucanase has additional fungal resistance properties.
Barley itself produces glucanases and chitinases, but the relevant genes are activated too late in the plant's development, so they fail to offer adequate protection, allowing pests to attack early. Furthermore the chitinases are produced in too small a quantity and their effect is too unspecific. Genes for plant glucanases from barley have however already been transferred to other organisms, e.g. grapevines, to confer fungal resistance.
One of the research projects now aims to examine whether beneficial fungi are also harmed by the production of the enzymes which break down chitin and glucan. Seventy to eighty percent of land plants form a symbiotic relationship with so-called mycorrhizal fungi which benefits both the plant and the fungi. Another project is looking at whether the production of enzymes in the plant has an impact on other plant characteristics and substances.
More from GMO Safety
- Transgenic fungus-resistant barley Effects on pathogenic and beneficial fungi, University of Giessen
- Transgenic fungus-resistant barley Effects on gene expression and plant substances, Friedrich-Alexander University Erlangen-Nuremberg
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