An international team of researchers co-led by a USDA scientist has sequenced the genomes of two fungal pathogens - one that threatens global wheat supplies and another that limits production of a tree crop valued as a future source for biofuel. The sequencing of the genetic codes of wheat stem rust pathogen and poplar leaf rust pathogen is expected to help researchers develop control strategies to address worldwide threats to wheat fields and tree plantations.
Wheat stem rust causes major epidemics of both barley and wheat worldwide. A strain known as Ug99 has spread across Africa and into Central Asia, and has been able to overcome most of the stem-rust-resistant wheat varieties developed over the past 50 years.
Poplar leaf rust can cause significant losses in poplar tree plantations. Poplar is an important crop for the wood industry and is becoming increasingly important to the biofuel industry in the United States and Europe because of its rapid and significant production of biomass.
According to Les Szabo, a lead researcher on this project, the study represents the first genome-wide characterization of any rust fungus, a diverse group of more than 6,000 species. The study, published in the Proceedings of the National Academy of Sciences, was a six-year collaborative effort of USDA's Agricultural Research Service, the U.S. Department of Energy Joint Genome Institute, the National Science Foundation, the Broad Institute of Harvard and the Massachusetts Institute of Technology, the University of Minnesota and the French National Institute for Agricultural Research.
"The threats these pathogens pose to two essential agricultural products are very real, and that makes it important to learn everything we can about them, from their molecular underpinnings to how they survive and spread infection," said Edward Knipling, administrator of ARS, USDA's principal intramural scientific research agency. "The research supports the USDA priority of developing new sources of bioenergy and promoting international food security."