A new international study conducted at the University of Haifa and the University of California (Davis) found for the first time genes that confer resistance to drought conditions in bread wheat. "A discovery of great importance that will allow the cultivation of wheat in extensive climatic conditions," said Dr. Gilad Gabai, the lead author of the article published in the prestigious journal Nature Communications
A new study conducted in collaboration between the University of Haifa and the University of California (Davis) was able to identify the genes (OPRIII) responsible for regulating the length of the roots in bread wheat, which will allow wheat with longer roots to reach the water found in deeper soil layers and yield more crops in drought conditions and a lack of precipitation. "This is the first time that a gene has been found that confers resistance to drought conditions in bread wheat. 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, a discovery of great importance that will allow the cultivation of wheat in more extensive climatic conditions," said Dr. Gilad Gabai, the lead author, in an article published in the prestigious journal Nature Communications..
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% of the global consumption of calories and proteins. Almost an absolute majority, about 95% of the commercial wheat used for human consumption belongs to one species, the bread wheat (Triticum aestivum), and almost all of the remaining five percent belong to a second species, durum wheat (Triticum durum). According to expert forecasts, by 2050 the demand for wheat will double, but today, not only is it not possible to increase the areas where wheat is grown - global warming and climate change are making more areas too dry to grow wheat, which relies on rainwater irrigation (land cultivation), which reduces the The possible supply of areas. Therefore, the estimates are that if we do not find other ways to increase the rate of wheat production, a significant shortage will be created, which could lead to a global food crisis. In light of this, one of the possible solutions for increasing wheat yields is through genetic improvement which will increase wheat yields without increasing the cultivation areas. About five years ago, the complete genome of bread wheat was sequenced, thanks to a large-scale international effort that included Prof. Zion Fahima and Prof. Assaf Distelfeld from the Institute of Evolution and the Faculty of Natural Sciences at the University of Haifa. Sequencing the genome paved the way for finding dedicated genes in bread wheat, which are responsible for the various processes in the wheat's growth.
In the current study, Dr. Gabai and Prof. George Dobkowski from the University of California (Davis), together with Prof. Fahima and doctoral student Hanchao Wang from the University of Haifa, and other researchers from various universities in the world were able to identify a gene cluster that is responsible for regulating the length of wheat roots.
Significant differences in yield especially in drought conditions
In the first phase of the research, the researchers identified wheat varieties in which significant differences were found in the yield of more than 2000 kg per hectare (hectare = 10 dunams) and in the biomass of the plants, but 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, it was 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, 5 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 the development of the roots in wheat using ground-breaking methods of genome editing and genetic engineering in wheat research that were recently developed in the laboratory of Professor Dobkovsky and were implemented by a team that included the doctoral student Wang under the guidance of Dr. Gabbay, who developed innovative Next tools Generation Sequencing (NGS) for detecting mutations in the wheat genome that occur as a result of genomic editing.
As mentioned, in the current study, the researchers were able to identify the OPR-III gene cluster and found that the level of gene expression, which was changed through genomic editing and molecular tools, or the number of copies of the gene that differs between different varieties of wheat, affects the length of the roots of the wheat. In addition, the researchers characterized the mechanism through which the genes affect the elongation of the roots and identified the secreted hormone that affects the growth rate of the roots.
Currently, the regulation in most western countries does not allow genetic improvement through artificial interventions to change gene expression. Alternatively, the gene can be transferred by natural hybrids of existing varieties. This is where the gene banks for wild grains come into the picture, one of the largest in the world is located at the University of Haifa and is managed by Dr. Tamar Krugman, the partner in the follow-up research being conducted in Haifa. "Our gene bank has thousands of varieties of wild wheat, from Israel and the world. After discovering the group of genes responsible for the length of the roots, we can now look for wild varieties that have an optimal level of expression of group-III OPR and cross them with bread wheat varieties, and thus develop new varieties of bread wheat in which the roots are longer and can produce a larger crop under Dryness," said Prof. Fahima.
The research was supported by the BARD US-Israel Agricultural Research and Development Fund, US Department of Agriculture, Howard Hughes Medical Institute and National Natural Science Foundation of China.
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