Wheat stack boosts resistance
CSIRO bio-engineers are developing new wheats with a stronger resistance against rust diseases.
Australia is expecting a strong wheat crop this year, but that would be threatened if a large outbreak of wheat rust occurred.
However, researchers at CSIRO say they can help combat this risk by “stacking” five resistance genes together.
This represents a major advance over conventional wheat breeding protocols, where individual resistance genes are added one by one.
The researchers have developed novel genetic technologies that combine and insert the five different wheat resistance genes together, using the bundling to prevent separation in subsequent breeding generations of the plant.
“Our approach is like putting five locks on a door – you’re making it very difficult to get in,” CSIRO researcher Dr Mick Ayliffe said.
“Rigorous field testing showed that our gene stack approach provided complete protection against the rust pathogens we were targeting.
“Successfully validating the effectiveness of our technology makes this approach an incredibly attractive opportunity to protect global grain crops.”
In Australia, wheat is a $6 billion per annum industry, and the wider Australian grains industry supports over 170,000 jobs.
It has been estimated that a disease outbreak of one of the world’s most virulent strains of rust – Ug99 – could cost the industry up to $1.4 billion over a decade.
Wheat provides around 20 per cent of the world’s calorie intake, making crop protection vitally important for world food security, with cereal rusts also affecting barley, oats, rye and triticale crops.
Dr Ayliffe says the latest study targeted stem rust, but the same technology can be used to breed against stripe and leaf rust diseases as well, and in different existing wheat varieties to add resistance.
“One of the genes we selected actually protects against stem, leaf and stripe rust diseases, so it’s entirely possible to include genes that also work against other rust species,” he said.
“We don’t know the limits of this new gene stacking technology yet. We currently have an even larger genetic stack with eight resistance genes in the lab, so even more protection against rust is possible.”
The results so far have been published in Nature Biotechnology.