The ongoing battle against rust
Rusts are a common fungal disease of plants, including many of Australia's cereal and horticultural crops.
Rusts are adaptable and evolve to overcome resistance. In 1999 a new virulent strain of stem rust was discovered in Uganda (so-called 'Ug99') which has spread to Iran and is encroaching on Asia. Ug99 is particularly devastating as it can overcome many of the resistance genes present in current wheat varieties, leaving many wheat crops vulnerable to infection.
A few years later a new virulent strain of stripe rust appeared, this time in Australia, and has continued to cause serious annual crop losses ever since. It is a constant battle for wheat breeders to try to develop new cereal varieties with effective and long-lasting rust resistance.
Attacking rust from all angles
We have been contributing to the global fight against rust for several decades. Our research has focused upon the interaction between the rust pathogen and the crops it attacks. Using our expertise in wheat genetics we investigate both plants' defence mechanisms and rusts' ability to infect host plants.
The result is genetic markers that allow breeders to identify wheat varieties containing resistance genes which prevent rust infecting the plant or help the plants successfully battle a rust attack. These markers can be used to enable conventional breeding of rust resistant wheat.
One aim is to stack multiple resistance genes into a single wheat variety, significantly increasing its resistance and the length of time we expect it to remain resistant. Our research may lead to new varieties of wheat that can help farmers in Australia, and elsewhere, supply wheat and wheat products to people worldwide.
There are other ways to help control rust, such as fungicides and crop management. Avoiding susceptible wheat varieties and removing wheat between seasons stops the fungus building up in the crop. Issues surrounding long term sustainability and environmental impact of pesticides mean the use of resistance genes remains the most cost effective and environmentally friendly approach to control the fungus.
Continually building the genetic arsenal
Australian crops have been protected for the past 60 years by the breeding of rust-resistant crop varieties that inhibit the development of rust diseases. To date we have provided wheat breeders with more than 20 genetic markers, helping the industry keep one step ahead of this costly disease.
The economic benefits of our rust research include higher yields for Australian grain growers and reduced costs through avoided fungicide application. A recent economic assessment estimates the net present value of CSIRO's rust research to the wheat industry is approximately $382 million, with $290 million attributable to CSIRO.
Rust is a major threat to global food security. We collaborate domestically and globally to achieve our goals.
Recent published achievements have added to our arsenal in the global fight to protect our crops from rust, including:
- Nature Genetics: A recently evolved hexose transporter variant confers resistance to multiple pathogens in wheat
- Nature Plants: The wheat Sr50 gene reveals rich diversity at a cereal disease resistance locus
Our cereal rust program is supported by domestic and international partners including the Grains Research and Development Corporation, Australian universities, Borlaug Global Rust Initiative, French National Institute for Agricultural Research (INRA), International Wheat and Maize Research Centre (CIMMYT, Mexico) and the Chinese Academy of Agricultural Sciences.