Fungus uses light to invade, attack wheat plants

According to scientists at the University of Western Australia, Parastagonospora nodorum produces an herbicide compound called elsinochrome which destroys plant cells when exposed to sunlight.

Researchers manipulated the the fungus' genome to trigger elsinochrome production, allowing scientists to observe the deadly compound's behavior inside wheat plants.

"To conserve energy, P. nodorum does not normally produce elsinochrome, however it does when infecting wheat plants," Heng Chooi, a molecular scientist and research fellow at UWA, said in a news release. "This has made it difficult up until now to know the identity of such small molecules that are produced by the fungus when infecting wheat plants and understand their contribution to the disease."

Elsinochrome belongs to a family of molecules called perylenequinones. When exposed to light, the molecules spawn reactive oxygen compounds capable of damaging cell membranes and proteins.

"When we deleted the gene in the fungus responsible for production of elsinochrome, we saw a reduced ability of the fungus to affect the wheat plant," Chooi said.

Scientists have previously observed the behavior of perylenequinone molecules, but never inside wheat plants, the most abundant commercial crop in the world. Researchers hope their findings, detailed in the journal Environmental Microbiology, will protect wheat crops from destruction.

"The study opens up new opportunities to find ways to stop the fungus from producing the herbicide compound or to make the wheat to become resistant and therefore less affected by the disease," Chooi concluded.