A new Israeli-US study has identified genes in wheat that can improve the crop’s resistance to drought.
“This is the first time that a gene has been found that confers resistance to drought conditions in bread wheat,” said Dr. Gilad Gabay, the lead author of the article published in the peer-reviewed journal Nature Communications.
“In light of the importance of wheat to the nutrition of the world population on the one hand, and the global warming that is increasing more and more the areas suffering from drought and making it difficult for agricultural crops, the discovery is of great importance that will allow the cultivation of wheat in more extensive climatic conditions,” he said.
Dr. Gabay, formerly of Hebrew University and the Israeli Ministry of Agriculture’s Agricultural Research Organization, is a postdoctoral researcher at the University of California-Davis whose team worked in collaboration with Haifa University.
The researchers found that genes known as OPR III were responsible for regulating the length of roots in bread wheat. Longer roots allow the wheat to find water in deeper layers of soil and yield more crops despite dry conditions and lack of rain.
Wheat is one of the three main grains on which the world’s diet is based, along with rice and corn. Wheat consumption in the world today is over 800 million tons per year, and it provides over 20 percent of the global consumption of calories and proteins.
Although world demand for wheat is expected to double by 2050, it is not possible to increase the areas where wheat is grown. Wheat relies on rain water irrigation, but global warming may be reducing the areas where it can grow.
Five years ago, the complete genome of bread wheat was sequenced, thanks to a large-scale international effort that included Haifa University Professors Zion Fahima. Sequencing the genome — a laboratory method used to determine the genetic makeup of a specific organism — paved the way for finding the specific genes in bread wheat responsible for its various processes of growth.
In the current study, the researchers identified the gene cluster responsible for regulating the length of wheat roots.
In the first phase of their study, the researchers identified wheat varieties in which significant differences were found in the yield of more than 2,000 kg per hectare and in the biomass of the plants. However, what caught their eyes was that these differences were greater under dry conditions.
In the second stage, through tests in wheat fields and hydroponic methods, the researchers found that these differences were caused by differences in the elongation of the roots.
In the third stage, using advanced genomic and bioinformatics tools, the researchers identified the segment of the genome where the genes related to the root structure in wheat may be found.
“This identification is considered extremely complex since bread wheat has a huge genome, five times larger than the human genome, consisting of three different sub-genomes that include six copies of each chromosome,” said Dr. Gabbay.
In the last step, the researchers were able to prove the role of the genes in development. During this process, they also identified a secreted hormone which affects roots’ growth rate.
Currently, regulations in most western countries prohibit the genetic improvement of plants through artificial interventions. However, the gene identified by the researchers can be transferred by natural hybrids of existing varieties of wheat.
According to researcher Dr. Tzion Fahima, this is where gene banks for wild grains come into the picture. He works in one of the world’s largest at Haifa University.
“In our gene bank there are thousands of varieties of wild wheat, from Israel and around the world,” Dr. Fahima said.
“After discovering the set of genes responsible for root length, we can now search for wild varieties that have an optimal level of expression of group OPR III and hybridize them with bread wheat varieties, and thus develop new varieties of bread wheat in which the roots are longer and which will be able to produce a larger crop under dry conditions,” he said.
