Stringent requirements for tomorrow's wheat varieties

January 28, 2013 - 06:30

Researchers around the world collaborate on mapping the genetic material of wheat. This will make it easier to develop new varieties with desired properties.

The objective for the wheat researchers around the world is to arrive at a genome sequence for bread wheat, and to make this freely available. (Photo: Colourbox)

Examples of desirable properties of wheat include good baking quality, high nutritional value, the ability to tolerate changeable weather conditions and resistance to sprouting damage and plant diseases.

"The aim is that wheat varieties of the future should be hardy and stable. They must tolerate changing weather conditions and climate change, provide good harvests and be of high quality. In order to bring this about, we must understand not just which genes are involved, but how these genes react," says grain researcher Ellen Færgestad Mosleth at the food research institute Nofima.

Started sixty years ago

Norwegian researchers have worked to improve wheat since the 1950s. At that time, the quality of Norwegian-grown wheat was very poor and hardly any went into food production.

An ambitious programme was established to improve the baking quality of Norwegian wheat varieties.

New varieties were developed and cultivation techniques were improved. Professor Erling Strand and Professor Kåre Ringlund of the Institute for Plant Culture at the Norwegian Agricultural College crossed Norwegian varieties with foreign ones to obtain new properties.

Their work improved both resistance to sprouting damage and gluten protein qualities. This laid the foundations for Norwegian production of bread wheat.

The pace of research on improving the quality of Norwegian wheat increased from the 1990s. And improvement came from finding out which genes and proteins were important for baking quality.

Researchers used biological markers for the genes of the best gluten proteins and studied how these affected the quality of Norwegian bakery products during the different processes.

Several researchers at Nofima and UMB chose wheat quality as a topic for their PhD-studies.

As a result of these studies, the focus of Norwegian wheat breeding became development of varieties with genes that provide strong gluten quality.

The research is carried out in close collaboration with the entire value chain, from farmer to baker.

"We have found genes that promote good gluten proteins, but we need to understand more about how these proteins are constructed, how the climate affects this structure and, not least important, what breaks them down in bad weather," says Mosleth, and continues:

!In particular, we look at the interaction between genetics and the environment. We wish to find genes that provide more stable quality in different climatic conditions. Mapping the genetic material of wheat will give us many of the answers."

Chromosome 7B is Norway's responsibility

The objective for the wheat researchers around the world is to arrive at a genome sequence for bread wheat, and to make this freely available.

The wheat genome contains the wheat's entire genetic information and is the code to its DNA. It is six times the size of the human genome and has three overlapping sets of chromosomes. This makes the work particularly extensive and complex. The quantity of data is so enormous that sequencing techniques have only recently become good enough to handle it all. The work is also made more complicated by the great similarities between the different chromosomes.

The researchers who work on mapping the genome sequence are affiliated to the International Wheat Genome Sequencing Consortium. The scientists responsible for mapping chromosome 7B are from Norway. This research group is being led by Professor Odd-Arne Olsen of the Norwegian University of Life Sciences. He explains that knowledge of the genetic material is a good starting point for understanding which genes affect various properties.

"If we know the genetic sequence of a genome, we can develop tools for selecting pants with the properties that we wish to refine. We have previously been able to study and exploit known genes to a certain extent, but now we have the opportunity to do this much more effectively and precisely," says Olsen.

At Bjørke Research Station near Hamar is an organisation called Graminor. Graminor is responsible for all plant breeding for agriculture and horticulture in Norway and it has an active role in mapping the wheat genome. With about 30 employees, this is a small company with a big responsibility in international terms. Director Idun Christie sees great utility value from their efforts, in the form of new and improved varieties.

Wheat breeding at Graminor today still relies on the kind of crossing of varieties that was done by professors Strand and Ringlund when they began the work of improving the quality of Norwegian wheat. These crosses result in thousands of offspring that are genetically different - the starting point for the meticulous work of selecting the best combinations.

"In the future we can develop effective methods for making this selection. We will know what we are looking for, that is to say which genes the offspring should have to achieve the best combination," says research scientist Muath Alsheikh, who is a molecular genetician at Graminor.

The genes are like a recipe book

Odd-Arne Olsen supports Alsheikh and adds that the more we know about wheat's genetic material, the faster we can produce offspring with the right combination.

"We are in the midst of a revolutionary paradigm shift that lay the foundations for progress in wheat breeding that will be at a completely different level to what has been possible up to now," says Olsen.

Genetic researcher Paul E. Grini of the Department of Molecular Biosciences at the University of Oslo explains that the genes are like a recipe book. When the book is opened, the cells can read what is there and receive instructions on what to do. As well as the letters in the book, we are now beginning to also understand more about how the individual genes, or pages in the book, are read.

Some genes can be marked so that they are easier to read, others cannot be read at all.

"This is called epigenetics, and can be of great significance for whether a gene is active or not.  We now have the opportunity to measure and register epigenetic markers in wheat, which will enable a new understanding of the interaction between the genes and what significance the individual genes have," says Grini.

He is researching the epigenetic regulation of seed development in the model plant Arabidopsis thaliana, and looks forward to continue this work with wheat.He finds it interesting that external conditions such as environmental stress can influence the epigenetic markers, and thereby how the genes are read.

"New research shows that some markers can be inherited by subsequent generations of plants.  This means that it is not just the letters in the recipe book that are important, but also the environment that has influenced the epigenetic markers over the generations. It is too early yet to say anything definite, but it is probable that we will have to think differently in future plant breeding research," says Grini.

The genome sequence will be freely available

When the wheat genome is mapped, the aim is that the results will be used internationally. The genome sequence will be freely available to all, and it is not possible to take out a patent on the genes, although it is possible to patent the use of individual genes or the use of specific genetic combinations in certain circumstances.

Professor Olsen gives an example:

"Identifying genes that give robust baking qualities will have great commercial value, but as genetic markers, that is to say markers used to identify relevant genes in plant breeding, and only when these are used with baking quality in mind."

"In Europe, this will be used in normal plant breeding work, not in the genetically modified plants that many people are so suspicious of," says Valborg Kvakkestad of the Norwegian Agricultural Economics Research Institute (NILF).

Kvakkestad recently completed her doctorate. She studied how various external conditions affect what kinds of genetically modified plants are developed and approved by the authorities. Now she intends to contribute to biotechnology projects by taking responsibility for the ethical, political, societal and environmental aspects.

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