Making wheat rust-resistant - Researchers respond to the global food crisis by enabling resistance of wheat to rust diseases

Date:09-15-2022

Wheat supplies about one fifth of all calories and proteins consumed by humanity. However, through the millennia, the process of cultivation has reduced the diversity of wheat varieties, and consequently modern wheat varieties are more vulnerable than their predecessors to diseases, pests, and climate hazards. The escalating climate crisis creates an urgent need to produce wheat varieties capable of thriving in extreme environmental and climatic conditions and withstanding pests and diseases.

An international research team that includes researchers from Tel Aviv University has isolated three disease-resistance genes from wild grasses, enabling resistance to rust diseases that cause severe damage to wheat yields worldwide.

It's in The Genes

The project was facilitated by several technological innovations that drastically cut down the time needed to identify and isolate genes from wild plant species and transfer them into cultivated plants.

"Since wheat first originated in our part of the world, wild cereals growing in our region are the progenitors of cultivated wheat, still carrying a rich variety of genetic traits that can be used to develop improved wheat varieties."

The three genes were isolated from plants preserved in the Liberman Okinow Gene Bank of Wild Cereals at the Institute for Cereal Crops Research (ICCR) at the George S. Wise Faculty of Life Sciences at Tel Aviv University. Two of the genes, providing immunity against stem rust disease, were isolated by an international team led by researchers from the UK. The third gene, isolated by researchers at TAU, provides resistance against two different diseases – leaf rust and stripe rust, currently exacerbated due to rising temperatures around the world.

Prof. Amir Sharon, Head of ICCR, says that isolating the genes was enabled by several technological breakthroughs, and that these novel technologies can also be used to isolate genes for other beneficial properties. Transferred into the genome of cultivated wheat, such genes will serve to generate better wheat varieties – featuring higher yields, and resistant to diseases, pests, and harsh environmental conditions. "Just as each of us carries only a small part of his/her grandparents' genes, cultivated wheat contains only a remnant of its ancient ancestors' genetic heritage. Since wheat first originated in our part of the world, wild cereals growing in our region are the progenitors of cultivated wheat, still carrying a rich variety of genetic traits that can be used to develop improved wheat varieties," explains Prof. Sharon.

"Certain traits of wild plants have already been incorporated into cultivated wheat over the years, however this great genetic potential remained mostly untapped, since, until recently, it took more than a decade to isolate a single gene. Today, thanks to several technological breakthroughs, especially genome sequencing and bioinformatics, we can isolate new genes in less than a year. Thus, in the past year alone, three genes providing resistance to various rust diseases were isolated from seeds of wild plants preserved in our gene bank. These genes, implanted in cultivated wheat, can significantly reduce damage from the relevant diseases with no need for pesticides - preventing yield losses while also protecting the environment."

In addition to disease resistance, Prof. Sharon's team is collaborating with researchers worldwide to isolate genes for other beneficial traits. Thus, for example, they work with researchers from Ben-Gurion University who recently isolated pest-resistance genes from wild wheat, and in our own Institute they've identified a new gene in wheat progenitors, that may provide endurance in an arid climate.

Prof. Amir Sharon & Dr. Arava Shatil Cohen in the lab

'Safe Box' to Tackle Climate Change

In addition to new methods for isolating genes, great advances have been made in biotechnology, specifically in technologies for gene transfer and genome editing. These technologies enable the transfer of new genes to crop plants, as well as introduction of changes into existing wheat genes.

"Essentially, the collection serves as a safe box for genes needed to create new, improved varieties of wheat that will give humanity larger crops and meet the challenges of climate change."

ICCR implements these new technologies, offering services of wheat gene transformation and genome editing to researchers in other institutes, as well as commercial companies. "With the support of the Chief Scientist of Israel's Ministry of Agriculture, and the Israeli Center for Genome Editing in Agriculture, we have established a center for wheat transformation and genome editing at ICCR," shares Prof. Sharon. "This is an important milestone, enabling us, for the first time, to perform effective wheat transformation here in Israel,″ says Prof. Sharon.

Dr. Arava Shatil Cohen, Head of the wheat transformation unit, adds: ″With these technologies we can implant new genes and use genome editing methods to give wheat new properties. We utilize our systems to promote research at ICCR and help companies and researchers from other institutions who wish to use this technology".

Today, ICCR's gene bank includes over 17,000 seeds of 20 different species of wild cereals, collected in Israel over the past 50 years. The collection is unique, both because of its large number of species related to cultivated wheat, and because a large portion of the plants preserved in the gene bank were collected in natural habitats that no longer exist due to rapid urban development in Israel. "Essentially, the collection serves as a safe box for genes needed to create new, improved varieties of wheat that will give humanity larger crops and meet the challenges of climate change," says Prof. Sharon. "The new technologies are the key to the safe box: they enable us to identify and extract the needed genes quickly and incorporate them into cultivated wheat."