DNA fingerprinting of rust pathogens

Dr Felicity Keiper is delving into the rust genome to gain a better understanding of how these pathogens adapt to overcome resistance in cereal varieties.

EFFORTS TO develop rust-resistant cereals arc often thwarted by the development of new rust strains that can attack previously-resistant cultivars. In Australia, these strains are believed to develop mainly by mutation (e.g. the recent development of leaf rust strains capable of overcoming the resistance genes Lr24 and Lr37 in wheat), or from periodic introductions from overseas (e.g. wheat stripe rust in WA in 2002).

The University of Sydney has been monitoring the occurrence of cereal rust strains across Australia for much of the past 80 years, and has a collection of rust isolates in liquid nitrogen that are crucial for research and cereal breeding. With the development of new DNA-based fingerprinting techniques, this collection provides a unique opportunity to look at evolution in the rust pathogens over long periods of time.

The fingerprinting methods developed in this project were invaluable in establishing the exotic origin of the wheat stripe rust isolate that appeared in WA in 2002, and are contributing to our understanding of how rust pathogens overcome the resistance of varieties. Felicity Keiper has established good links with researchers in North America, who are planning to fully sequence two rust genomes. This information will give an unprecedented opportunity to investigate the genetic mechanisms operating in these pathogens.

Program 3 Contact: Dr Felicity Keiper 02 9351 8811 email keiperf@camden.usyd.edu.au