DNA delivers wheat rust breakthrough

Wheat rust breakthrough from DNA research

Farm Online News
Rust infection on adult wheat stems, a fungal disease that can cripple wheat crops. Photo by Robert Park.

Rust infection on adult wheat stems, a fungal disease that can cripple wheat crops. Photo by Robert Park.


Discovery provides powerful tool to tackle crippling fungal disease


SCIENCE has taken a significant step in the long-running battle to tackle the crippling wheat rust fungus.

In a world first, an international team including Australian researchers has developed a DNA test to check a plant’s resistance to rust.

The test only takes several hours, compared to weeks for other methods, greatly improving the chances of saving a crop which could otherwise be severely reduced by rust.

“For the first time it will be possible to do DNA testing to identify whether a rust in a wheat crop anywhere in the world can overcome a rust-resistance gene, called Sr50, which is being introduced in high-yielding wheat varieties,” said University of Sydney’s lead researcher Professor Robert Park.

“This will indicate whether or not a given wheat crop needs to be sprayed with expensive fungicide quickly to protect against rust – which would otherwise devastate the crop in a matter of weeks.”

Rust is a common fungal disease of cereal and horticultural crops and occurs in most growing regions across the globe. It is an ever-evolving challenge.

The new diagnostic test is a significant step in the struggle to keep up with rust, which continually changes to produce new pathogen strains.

A new strain of stem rust emerged in Uganda in East Africa in 1999 and is spreading through the Middle East into Asia.

“It’s like an ongoing arms race. We’ve got to keep one step ahead of this changing pathogen,” Professor Park said.

“The last major epidemic of wheat stem rust in Australia alone, in 1973, caused $300 million in damage. Imagine what that would be today.”

Dr Peter Dodds from CSIRO Agriculture and Food said the breakthrough would help uncover the fundamental processes at play when rust attacks a plant.

“Our results so far show the plant immune system is able directly to recognise the fungal protein. We are gaining a better understanding of the whole process, what’s going on at the protein level, at the gene level.”

The research offers significant potential for food security, given the developing world is expected to need 60 per cent more wheat 2050, Dr Dodds said.

“Now that we’ve identified how stem rust strains are able to overcome Sr50 resistance – by mutation of a gene we’ve identified called AvrSr50. This information can be used to help prioritise resistance genes for deployment.”

The research project also included UK’s Rothamsted Research, the University of Minnesota and the United States Department of Agriculture.


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