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Will one Israeli plant save the world from starvation?

A new study found that genes from an Israeli wild plant may help protect wheat from one of the biggest threats to its existence

The results of the study show that the gene found in the Sharon wheatgrass gives the plant immunity against a wide variety of variants of the cane weevil. Photo: Dave Hansen
The results of the study show that the gene found in the Sharon wheatgrass gives the plant immunity against a wide variety of variants of the cane weevil. Photo: Dave Hansen

The continuation of the war in Ukraine also brings with it the continued increase in food prices in the world. Russia and Ukraine are responsible for More than a quarter of the world's wheat supply, and the production and export disruptions cause different countries, including Israel, to compete for alternative sources of wheat. It is no wonder that difficulties surrounding the supply of wheat cause concern, considering that it is a grain that is a basic component in the diet of a large part of the world's population - 770 million tons The wheat that is produced every year is sufficient about 20 percent Global calorie consumption. But despite the supply problems that can be caused by human wars, the greater danger may be for doughs Ours is actually a disease unknown to the public called cane blight, which in recent years has destroyed entire fields of wheat in large areas of the world.

For thousands of years, the war between the farmers and the cruel fungus has been raging Puccinia graminis, which causes disease. However, bNew research Conducted in collaboration with Israeli researchers, a special resistance to the disease was found in an Israeli wild plant - an ancient relative of modern wheat, which may provide the victory blow for humanity and ensure the survival of the wheat fields that will feed us in the future. So how did modern wheat lose the protections that its natural relatives had in the past? And what makes Israel the ideal place to find genes that will help us grow food In a world of climate crisis?

Until now, farmers have used different methods to deal with cane rust. One of them is the use of chemical pesticides - but it has a number of significant disadvantages. First, pesticides are expensive, so they are not available to poor farmers in many parts of the world. Second, when used, the pesticides contain toxic chemicals that pose a danger to the environment, because they may accumulate in the water and soil of the growing area. Furthermore, the fungus that causes the rust disease is able to adapt to pesticides, so that over time, their effectiveness against it decreases.

The strain that also damages resistant wheat

method more successful From an economic and environmental point of view, the way to deal with rust is to develop wheat varieties that have genetic resistance to the disease - so that there is no need for pesticides to prevent its development in them. Such a solution has proven to be effective in the past: outbreaks of cane rust have always been frequent, but thanks to cooperation between researchers and farmers, wheat varieties resistant to the disease have become common around the world since the 50s – which resulted in a dramatic reduction in the number of outbreaks.

However, in the late 99s, a strain of the cane weevil called Ug50 was discovered in Uganda, which overcame the resistance of common wheat species. Since then, outbreaks of the new cane blight have occurred in Ethiopia, southern Italy and western Siberia, causing the loss of tens of millions of dunams of produce. In an outbreak situation, the disease can cause a crop loss of 100 to XNUMX percent. Therefore, the race to find new genes that will give wheat resistance even to the new cane rust is currently occupying many scientists.

It should be noted that the damage caused by rust diseases is getting worse due to the climate crisis. "Due to the increase in temperature in the world, in the last 4-3 years severe outbreaks of rust have occurred in areas of Europe where the fungus was not able to survive in the past," says Prof. Amir Sharon, a member of the School of Plant Sciences and Food Security of the Faculty of Life Sciences and head of the Research Institute Cereals at Tel Aviv University, which is involved in the new research.

Israeli hope

The new study was carried out by an international team that included, among others, researchers from the University of Minnesota in the USA and Tel Aviv University. Through Use of advanced genetic search tools Under the name "Mutant Hunter", the researchers scanned the genomes of plants that showed immunity to cane rust, and compared them to the genomes of those that were not immune to the disease. They identified a candidate gene in the wild plant Ben-Hita Sharoni (Aegilops sharonensis), an ancient relative of modern wheat, which grows exclusively on the coasts of Israel and southern Lebanon. This plant was identified as a candidate for conferring immunity to rust more than a decade ago, but the new study was the first in which the relevant gene was isolated, and transplanted into another species: the gene, which the researchers called Sr62, they planted in a known type of wheat that is vulnerable to rust, and then tested its resistance against different types of cane rust.

The main change in wheat crops occurred in the middle of the last century, with the "Green Revolution": the development of short wheat species by the American scientist Dr. Norman Borlaug, which made it possible to bring about a very significant increase in the wheat crop for a given area. There is no doubt that this was a landmark discovery, which contributed significantly to the reduction of world hunger. However, in the long run, it also had less positive consequences. "Suddenly they stopped growing traditional crops, and started using only Borlog varieties - and that's how we ended up with a narrow and fragile biological diversity that is vulnerable to diseases," says Dr. Einav Maizlish Gethi, director of the Center for Genetic Resources and Seed Quality at the Volcanic Institute. "The way to solve this problem is to use with biological material from another source and enrich Borlog's varieties with it," says Maizlish Gethi. According to her, Ben-Hita Hasharoni is an example of a possible source for this.

As mentioned, the gene found in Ben-Hita Hasharoni is not the first to be found that confers immunity against cane blight to wheat, since in the 50s resistant wheat species were developed to which the blight fungus adapted and overcame them. Therefore, there is a fear that over time the fungus will also learn to overcome the immunity conferred by the new gene. "We learned that genes can wear out, so the approach is to take several genes at once and put them in as a unit," says Sharon. "Thus, the probability that the disease will be able to overcome everyone at the same time is minimal."

"We are at the beginning of a revolution that will include moving to advanced tools of Genetic engineering and editing, through which any company or organization will be able to take appropriate genes and insert them into their wheat variety, without affecting any other trait - such as giving a vaccine against a disease," concludes Sharon.

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