Gene discovery may halt worldwide wheat epidemic

Credit: UC Davis

University of California, Davis, researchers have identified a gene that enables resistance to a new devastating strain of stem rust, a fungal disease that is hampering wheat production throughout Africa and Asia and threatening food security worldwide.

The discovery by UC Davis wheat geneticist Jorge Dubcovsky and his team will help breeders more quickly develop varieties that can fend off the deadly pathogens and halt a worldwide wheat epidemic. The findings were recently published in the journal Proceedings of the National Academy of Sciences.

Wheat and stem rust have been in an evolutionary arms race for more than 10,000 years. In the 1950s, a major epidemic of the disease spread through North America and destroyed up to 40 percent of the wheat crop, the world’s second most important grain next to rice.

Since then, scientists have developed rust-resistant varieties to boost wheat’s immunity to stem rust. But the pathogens are making a comeback. A new strain of the stem rust — called Ug99 after it was discovered in Uganda in 1999 — is spreading throughout the region. About 90 percent of the wheat varieties grown worldwide are susceptible to Ug99.

“Ug99 has expanded to most of the wheat-growing regions in Africa and has crossed the Red Sea to Yemen and Iran,” said Dubcovsky, a professor with the UC Davis Department of Plant Sciences and a Howard Hughes Medical Institute investigator. “Ug99 is now at the door of the Punjab region — the bread basket of Asia — and identification and deployment of effective resistance genes are critical to mitigate this threat.”

Dubcovsky and his team identified three different resistance forms of Sr13, a gene from pasta wheat that is effective against Ug99 and another group of virulent stem-rust strains from Yemen and Ethiopia. In 2013, Dubcovsky and fellow researchers discovered another gene called Sr35 that also provides resistance to Ug99. The team is close to identifying a third gene that confers protection from the virulent strain.


To develop better varieties, breeders cross plants with desired traits and select the best offspring over multiple generations. Once stem-rust resistant genes have been identified, breeders can use molecular markers (specific regions of DNA) to select for the genes at the seed or seedling stage. This accelerates the crop-improvement process.

These molecular markers allow breeders to pyramid multiple stem-rust-resistant genes in the same plant to extend the durability of resistance.

“Wheat provides a substantial amount of calories and proteins consumed by humans,” Dubcovsky said. “We hope that a better understanding of the wheat-rust pathosystem will speed the development of new strategies to control this devastating pathogen.”


Media Contact

Jorge Dubcovsky
[email protected]

Original Source

  1. irnwrkr says

    GMO! Oh no! Ban this stuff so millions can starve.

    1. edgeben says

      Irnwrkr, while your point is well taken, this article is not talking about genetic engineering. It is talking about identifying genes in wheat and molecular markers for those genes that breeders can then use to track them in conventional crosses. It makes the breeding process much more efficient and predictable.

      1. arctic_front says

        Did you not read your own comment? GMO is GMO. You can tip-toe around it all you want, but these scientists are genetically modifying the wheat. And this is a GOOD THING. Same goes for many other foods.

        1. edgeben says

          Arctic_front, I am a wheat breeder. There is no need to confuse people by needlessly confusing the terminology. I’ve modified wheat many times through conventional breeding. But conventional breeding is not the same as genetic engineering and your facetious attempt to confuse the two doesn’t help. This article is talking about developing markers for genes that can be used in conventional breeding. They could also be used in genetic engineering, but don’t require the use of genetic engineering.

      2. John Galt III says

        GMO is when you insert new genes, drop existing genes, cross breed, genetically select and so on and it can be done in a garage, in outer space , in a field, in a lab and so on

        The ensuing new plant has no clue as to where, when by whom or how it was accomplished.

        There is no useful distinction. Opponents of GMO suffer from orthorexia nervosa or are just plain stupid They will lose.

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