Identification of the wheat Yr15 resistance gene promotes a durable solution for controlling yellow rust, a major threat to food security for millions of people, believes an international research group led by Natural Resources Institute Finland (Luke), the Institute of Biotechnology at the University of Helsinki, and the University of Haifa.

Yellow rust is a devastating fungal disease threatening much of global wheat production, the problem increasing with climate change. Wheat is the most cultivated food crop globally, but more than five million tons of wheat harvest, valued at around one billion USD, are estimated to be lost annually due to yellow rust, affecting food security and affordability for millions of people.

In an international collaboration involving about 30 researchers at 14 institutions in 8 countries, the researchers identified and analyzed Yr15, a broad-spectrum resistance gene derived from wild emmer wheat, the ancestor of durum (pasta) wheat. The work unlocks interesting opportunities for breeding more resistant wheat varieties.

“Aaron Aaronsohn discovered wild wheat in 1906, and believed it would hold the key to breeding disease- and stress-resistant crops. With the work on Yr15, Aaronsohn’s vision is bearing fruit,” said Prof. Alan Schulman from Natural Resources Institute Finland (Luke).

“Crop wild relatives, like wild emmer wheat, are a great reservoir of useful genes and need conservation. Combined with a genome sequence – which became available this year – rapid advances in breeding are now possible,” said Schulman.

A horse race between pathogens and resistance

Although new resistance genes are frequently discovered from various sources, fungi rapidly evolve to overcome them, rendering the majority of the world wheat production susceptible to epidemics. However, Yr15 has been remarkably stable over several decades.

“We now understand why Yr15 is so robust – its structure is highly unusual for a disease resistance gene. The project showed, though, that related genes are present in many plants, opening the door to widespread use,” Schulman added.

The results of the study Cloning of the wheat Yr15 resistance gene sheds light on the plant tandem kinase-pseudokinase family have been published on Nature Communications, issue 9/2018.