Researchers smash wheat rust mystery

DISEASE: Research by the CSIRO and others has solved a 20-year mystery surrounding wheat rust disease and Australia will now be better protected.
DISEASE: Research by the CSIRO and others has solved a 20-year mystery surrounding wheat rust disease and Australia will now be better protected.

An Australian disaster costing $500 million and possibly affecting the Mid North is now less likely after research into wheat rust disease.

Scientists have uncovered the origins of the world's deadliest strain of cereal rust disease - Ug99 - which threatens global food security. It solved a 20-year-old mystery. The discovery will make it possible to develop better methods to screen for varieties with strong resistance to disease.

Australian crops have been protected for the past 60 years by the breeding of rust-resistant varieties. "It has been estimated that a nationwide outbreak of Ug99 here could cost Australia up to $500 million in lost production and fungicide use in the first year," said a researcher.

"There is some good news, however, as the more you know your enemy, the more equipped you are to fight against it.

"Knowing how these pathogens come about means we can better predict how they are likely to change in the future and better determine which resistance genes can be bred into wheat varieties to give long-lasting protection."

Earlier this year, CSIRO worked with the University of Minnesota and the 2Blades Foundation to achieve good results in wheat resistance by stacking five resistance genes into the one wheat plant to combat wheat stem rust.

This latest research is the result of a collaboration between scientists from CSIRO, the University of Minnesota, University of the Free State, and Australian National University.

The breakthrough came as Dr Figueroa's group was sequencing Ug99 (then at the University of Minnesota) and at the same time a CSIRO team led by Dr Peter Dodds was sequencing Pgt 21 in Australia.

RIGHT: Drs Narayana Upadhyaya, Rohit Mago, Peter Dodds, and Melania Figueroa.

Pgt21 is a rust strain that was first seen in South Africa in the 1920s and believed to have been carried to Australia in the 1950s by wind currents. When the two groups compared results, they found the two pathogens share an almost identical nucleus and therefore half of their DNA.

"There was an element of serendipity at play in this work. We never expected that Ug99 and an Australian isolate might be related but only through a multi-continental collaboration was it possible to make the connections needed to achieve this discovery."

Background

This research was supported by the 2Blades Foundation, USDA-Agriculture and Food Research Initiative (AFRI) Competitive Grant (Proposal No. 2017-08221), an USDA-NIFA Postdoctoral Fellowship award (2017-67012-26117), an ARC Future Fellowship (FT180100024) and the University of Minnesota Lieberman-Okinow and Stakman Endowment.

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