WASHINGTON — A consortium led by the U.S. Department of Agriculture has fully sequenced the genome of the pathogen that causes Mycosphaerella graminicola, or septoria tritici blotch, a disease found in all wheat growing areas of the world that can cause up to 50% yield losses if untreated.

“Having a complete sequence of the M. graminicola genome will give researchers across the globe the tools necessary to mitigate the damage this pathogen causes to wheat crops,” said Edward B. Knipling, administrator of the Agricultural Research Service, the U.S.D.A.’s main scientific research arm.

M. graminicola has the ability to infect the host plant without the plant mounting an adequate defense, if any, according to the U.S.D.A. The pathogen has a long latent stage during which it takes nutrition from the plant and evades the plant’s natural defenses. During a “silent period” the pathogen switches to a disease-causing stage.

“A lot of pathogens infect host plants by penetrating the plant’s cell wall,” said Stephen Goodwin, plant pathologist at the A.R.S. Crop Production and Pest Control Research Unit in West Lafayette, Ind., who led the research. “But this organism grows into the plant’s natural openings, which are normally used for gas exchange.

The pathogen then grows in between the cell walls without triggering defense responses that are designed to stop infection.

“We don’t know what happens in that switch from the latent phase to the pathogenic phase. The gene sequence will allow scientists to look at the expression of all of those genes involved in the transition period.”

The results were published in PLoS Genetics. The research team included members from the U.S. Department of Energy’s Joint Genome Institute as well as scientists from Australia, Brazil, France, Germany, Iran, Mexico, The Netherlands, Switzerland and the U.K.