By mapping the family tree of the fungus that causes ‘Crown Rot’ in wheat, CSIRO Plant Industry has taken a major step towards controlling the devastating disease.

With a clearer picture of the fungus’ genetic history and development, researchers hope they will be better equipped to find longer lasting and more effective strategies to reduce the impact of Crown Rot – a disease which currrently costs the wheat industry around $50 million in lost yield every year.

“There are many strains of Fusarium pseudograminearum that cause Crown Rot in Australia,” says CSIRO Plant Industry’s Dr Sukumar Chakraborty. “Each one has a different level of virulence and therefore a greater or lesser impact on the wheat crop.

“New strains of fusarium are also always developing making pin-pointing our target for breeding fusarium-resistant wheat varieties difficult.”

In collaboration with researchers in other countries where Crown Rot is also a serious problem – Canada, New Zealand, South Africa and the USA – Dr Chakraborty and his team collected and analysed over 55 strains of Fusarium pseudograminearum.

The broad range of strains used in the study provided valuable information about the genetic diversity of fusarium – a factor that allows fusarium to be such a problem.

“We wanted to find out if virulent strains were genetically different to less virulent strains and whether this difference is consistent across strains from different countries and regions,” Dr Chakraborty says.
Using a technique called gene sequencing, Dr Chakraborty tracked four important genes across the fusarium strains and found that they all belonged to a single family-group consisting of promiscuous inter-breeding members.

“This means that virulent strains of fusarium can develop more easily and can share their genes with other strains of fusarium when they spread into new areas,” he says.

“We are further studying links between the Australian family group of fusarium and their virulence to ensure that new Crown Rot-resistant wheats are resistant to all strains.”

Dr Chakraborty’s team has set up a wheat field trial in Queensland to monitor fusarium infection for early signs of any new fusarium strains evolving.

This, coupled with the identification of resistant wheats, will help in the breeding of the most effective fusarium resistant wheat varieties in the future.

This research is supported by the Grains Research and Development Corporation.

For more information on this fusarium research visit the Helping wheat beat fusarium information sheet.