Background/context:

Fusarium wilt of cotton, caused by Fusarium oxysporum f.sp. vasinfectum (Fov) has become a significant constraint to cotton production in Australia, since it was first recognised on the Darling Downs in Queensland in 1993. The estimated loss in crop production from fusarium wilt is estimated at $100 million per year while flow-on losses to cotton-ginners, contractors and consultants, machinery and chemical suppliers is estimated to be several hundred million dollars per year. Currently, most of the high yielding varieties are susceptible to Fusarium wilt. Disease control measures rely heavily on the use of varieties with enhanced resistance to the fungus and disease prevention strategies to limit the spread of the pathogen in cotton production areas. Early detection and identification of the disease in clean areas is critical, as the available disease prevention strategies must be implemented as soon as possible to be effective.

 Aim:

The project aimed to develop a DNA-based diagnostic test for rapid and accurate identification of the two Australian genotypes of Fov, and to validate the application of the Fov DNA diagnostic test for identification of fusarium wilt directly from infected plants, seed and infested soil.

Major Outcomes:

Real-time polymerase chain reaction (PCR) assays were developed to detect and differentiate the two Australian genotypes. The assay was recently used to prove that an outbreak of Fov in cotton growing regions around Athens (Greece) did not originate from clean seed imported from Australia. While the usefulness of the assay in soil testing to differentiate strains is in question, the assay is a highly effective tool for differentiating strains of Fov in pure culture and from plant extracts. 

The diagnostic test developed in this project will help cotton growers to detect the pathogen in soil and, in turn, help Australia to safeguard its US market for cottonseed exports. The net benefits afforded from the availability of this test have been calculated at around $17 million – a 12-fold return on the Centre’s investment in this project.

For more information contact:

Ms Linda Smith
Department of Primary Industries and Fisheries
Phone: +61 (0)7 3896 9358
Email: Linda.Smith@dpi.qld.gov.au