Unlocking the secrets of ancient wheat to battle disease
Posted By Ilana Teitelbaum On May 7, 2009 @ 1:00 am In | No Comments
A wheat field in the north of Israel. After 10,000 years of domestication, wheat has lost its resistance to disease and drought. Picture courtesy of Wikipedia.Bread might be the staff of life, but beyond the romantic images of amber waves of grain, there is a sobering reality: Cultivated wheat crops worldwide are constantly battling the effects of stripe rust, and often losing the fight.
In the US alone, stripe rust wreaks $150 million in damage per year. In developing countries, where wheat is a central staple, the consequences to populations can be much worse.
The key to protecting the world’s wheat crops from this rapacious disease is growing wild in Israel, according to Professor Tzion Fahima of Haifa University’s Department of Evolutionary and Environmental Biology.
Wild wheat, which was discovered in Israel 100 years ago by Romanian-born botanist Aaron Aaronsohn, is believed to be the original wheat plant, before wheat became domesticated. And like wild animals, wild wheat is much tougher and more resistant to diseases than its domesticated counterpart.
In collaboration with a team of researchers at the University of California-Davis, Fahima is researching the genetic characteristics of wild wheat, with an aim to improving cultivated wheat through biotechnology.
Vital traits lost during domestication
They’ve discovered a gene in wild wheat that provides resistance to stripe rust, which, if transferred to cultivated wheat, can help prevent eight different strains of the disease. Their findings were recently published in Science Magazine.
The wheat crop from which we make bread, pastas and other foods today is the result of 10,000 years of domestication.
“During domestication, the wheat plant was improved, and more yields were achieved, which fits with agricultural practices today,” Fahima tells ISRAEL21c. “But many traits and genes were lost during domestication. Now we’re looking for genes which were lost, to bring them back to cultivated wheat.”
These lost genes can be transferred into cultivated wheat via one of two ways: Either through a process called “classical breeding” which can take about five years, or through genetic engineering, which would take six months to a year.
Fahima favors genetic engineering, and believes that despite the controversy that surrounds the topic, genetically engineered wheat is the way of the future.
Fahima’s research into the genetic advantages of wild wheat doesn’t stop at resistance to stripe rust. His lab, in collaboration with the group led by Prof. Jorge Dubcovsky at UC Davis, has also discovered a gene that can increase the grain protein and mineral content in wheat – wild wheat is much richer in these nutrients than cultivated wheat. These findings were published in Science Magazine in 2006.
A major source of proteins and minerals
“We tend to think of bread as a major source of carbohydrates, but it’s also a major source of proteins,” explains Fahima. Protein is also important for the quality of breads and pastas.
Meanwhile an increase of the mineral content in wheat, such as the amounts of iron and zinc, can be vital for nutrition. This is especially true for poor populations, which get most of their calories from bread. In some developing countries people often get up to 60 percent of their daily caloric intake from bread.
“If the bread they consume is not rich in protein and minerals, nutrition becomes problematic,” says Fahima.
Yet another aspect of Fahima’s research is the study of making wheat resistant to drought, since wild wheat is far more drought-resistant than cultivated wheat. The research is particularly timely, as drought is one of the predicted effects of climate change.
The process of making wheat drought-resistant is complex, since there are multiple genes involved, but it is one of Fahima’s long-term projects, in collaboration with Prof. Yehoshua Saranga, at the Hebrew University in Rehovot.
Right now, though, Fahima’s focus is on the resistance gene that can protect so many wheat crops from disease. “This gene does not exist in the gene pool of cultivated wheat, and can be used to improve cultivars around the world,” Fahima concludes. “We need to transfer this gene.”
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