Scientists Learn More about Wheat Leaf Rust Fungus

Up to 60 resistance genes have been known to combat Puccinia triticina, the
fungus that causes wheat leaf rust. But the pathogen is so genetically
diverse and quick to adapt that most wheat resistance genes prove
ineffective within a few years. Never-the-less, scientists with the Agricultural Research Service say they are now better equipped to keep track of it.

Scientists have found that the strains of P. triticina infecting wheat in North
America fall into five genetically distinct groups, with two widely
distributed groups accounting for 90 percent of the total population. The
five groups also differ in their ability to overcome a number of resistance
genes, an indication that different groups of P. triticina develop virulence
traits at different rates.

The work will help researchers identify the origins of emerging strains of P. triticina,
unravel clues about migration patterns, monitor shifts in virulence and figure out why some resistance genes are more effective and long-lasting than others.