Background/context:

Sugarcane smut is a serious disease in most sugarcane producing countries. Smut appeared in WA in 1998 and while Qld and NSW are still smut free, the threat to these industries is very high. Smut, caused by the fungus Ustilago scitaminea, can result in yield losses of 20-100%. In 2000, orange rust, caused by Puccinia kuehnii, devastated the once top variety Q124, causing the industry over $150 million in yield losses. For both pathogens, the industry had to respond to the outbreaks without a full understanding of the pathogen’s population structure. Successful disease management strategies and deployment of resistance requires an understanding of variation in the pathogen population.

 Aim:

This project aimed to use molecular markers to assess the genetic diversity of orange rust from Australia, PNG, Indonesia, and historic herbarium collections; to extend a preliminary study on genetic diversity in sugarcane smut, with emphasis on South-East Asia; and, to use the information gained from the diversity studies to estimate the risk of new strains appearing, and make recommendations about this risk to assist plant breeders.

Major Outcomes:

This project has since contributed knowledge about the genetic makeup of the two pathogens and has identified a number of quarantine issues from orange rust and smut which could place the Australian sugar industry at risk. Conditions for the long term storage of orange rust material have been developed. Reliable spore germination conditions have been established and incorporated into a contained detached leaf inoculation system. For sugarcane smut, research results have demonstrated the need to screen Australian sugarcane varieties in areas where divergent isolates occur. Ten Australian varieties have been sent to PHILSURIN, the Philippines, and the Yunnan Sugar Research Institute, China, to be screened with local smut isolates to assess their reaction.

For more information contact:

Dr Barry Croft
Bureau of Sugar Experiment Stations
Phone: +61 (0)7 5496 3357
Email: BCroft@bses.org.au