Plant infection mechanism discovered

WASHINGTON, July 23 (UPI) -- Scientists say they've identified the method several disease-causing microbes use to infect plants and cause disastrous blights in crops in Africa and Asia.

The mechanism is used by a fungus currently causing wheat rust epidemics in Africa and Asia and by a kind of parasitic algae called oomycetes that caused the potato blight and resulting famine in 19th century Ireland, a National Science Foundation release said Thursday.

The researchers also found evidence suggesting the microbes might infect humans and animals through the same newly discovered mechanism. Human diseases caused by fungi include valley fever and several infections common to AIDS patients, the report said.

When the microbes come in contact with a host, an infection is initiated by secretion of a special protein into spaces between the host's cells, the study found. Like a key that opens a locked door to an invader, one particular part of the protein unlocks the host cell to an invasion and infections by the rest of the protein.

The invading protein disables the host cell's immune system and is free to spread unchecked throughout the host's tissues, the study found.

"Our findings suggest broad new strategies for combating the most damaging diseases of the world's major food crops, including wheat, rice, maize and potatoes, as well as several nasty human diseases," Brett Tyler of the Virginia Bioinformatics Institute at Virginia Polytechnic Institute said.