Reactions of resistant and susceptible selections of Sharon goatgrass to wheat stem rust.A native Israeli wheat species is the likely botanic “antidote” to a new fungus strain that threatens 70 percent of the world’s wheat crops and is relentlessly moving north from Africa. It is already in Yemen and if prediction models are correct, the fungus may enter Israel soon.
Sharon goatgrass (Aegilops sharonensis), which grows on Israel’s coastal plain and a few places in Lebanon and is a distant relative of cultivated bread wheat, is highly resistant to the fungus, called Ug99.
Researchers at the University of Minnesota (UoM), who are working with botanists at Tel Aviv University (TAU), have found that Sharon goatgrass is almost completely safe from the fungus, which was discovered eight years ago in Uganda. Their study on the resistance of the Israeli wheat species has just been published on nine pages in the American Phytopathological Society’s journal, Plant Disease.
The research – by Prof. Brian Steffenson, a UoM plant pathologist, along with lead author Pablo Olivera (a UoM doctoral student), co-author Prof. Yehoshua Anikster of TAU’s institute for cereal crops improvement and J.A. Kolmer of the US Department of Agriculture – offers hope to plant scientists who are combating the fungus disease called stem rust.
This fungus, named for the red-orange pustules it produces on the tissue of infected plants, can wipe out wheat crops. In 1999, Ug99 was discovered in Uganda. Able to attack 70% of wheat varieties around the globe, it has already spread through the Horn of Africa.
Anikster calls Ug99 “a very dangerous threat” to Israeli wheat, which is cultivated on 850,000 dunams in the country. “The short-term solution for this disease is to apply fungicides to the wheat, but this comes with an economic and environmental cost.”
The Israeli and American scientists are collecting more of the species for long-term storage in a TAU gene bank. As for the current threat posed by Ug99, the solution will not come overnight. Eitan Millet, a TAU wheat geneticist, said “transferring Ug99 resistance from Sharon goatgrass into wheat is a long and laborious project requiring five or more years of work.”
However, success in transferring resistance from Sharon goatgrass into wheat has been achieved for other plant diseases, so it definitely is practical. Steffenson, who said that “Israel is a very special place with regards to the wealth of wild cereal species,” noted that “the most effective, alternative solution for combating this disease is through the use of resistant wheat varieties.”
Sharon goatgrass has high levels of resistance to Ug99, a finding that is “not altogether surprising.” Even though Israel is a very small country, it has a wealth of genetic diversity in wild progenitors of wheat, barley, and oats. “Whenever a new outbreak of a disease occurs, the solution to the problem can often be found in the wild species,” said Steffenson.
Anikster added that “the genes carried by these wild species are important for cereal production far beyond Israel’s border.”
But Sharon goatgrass populations are threatened here because its primary habitat is along the coast, where the land is being developed for housing. The contraction of Sharon goatgrass populations may result in the loss of valuable genetic diversity needed for protecting wheat from future disease threats, added Olivera.
(Reprinted with permission from The Jerusalem Post)