An international team of researchers co-led by a University of Minnesota 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 (Puccinia graminis) and poplar leaf rust pathogen (Melampsora larici-populina) is expected to help researchers develop control strategies to address worldwide threats to wheat fields and tree plantations. The study, which was published this week in the early online edition of the Proceedings of the National Academy of Sciences, was a six-year collaborative effort of USDA's Agricultural Research Service (ARS), the U.S. Department of Energy, the National Science Foundation, the Broad Institute of MIT and Harvard, the University of Minnesota and the French National Institute for Agricultural Research.
The study represents the first genome-wide characterization of any rust fungus, a diverse group of more than 6,000 species, according to Les Szabo, a lead researcher on the project. Szabo works at the ARS Cereal Disease Laboratory on the university's St. Paul campus and is a member of the plant pathology department faculty.
Rust fungi are obligate biotrophs that depend on living tissue of their hosts for survival. These pathogens secrete proteins that enable them to block the host plant's defenses and steal nutrients. The research uncovered evidence that both pathogens have a large repertoire of "effector" proteins, an indication that they likely have adapted and co-evolved with their host plants, according to the study authors.
Because they need a host to survive, the pathogens can't be cultured in a laboratory and are notoriously hard to study. But the genetic sequencing opens a window into the never-ending arms race between these pathogens and their hosts, Szabo said.
|Contact: Patty Mattern|
University of Minnesota