Study shows how plants fight pathogens

Columbia, Mo. -- U.S. scientists said they've discovered how plants sense and resist attacks by pathogens in a study that might lead to enhanced disease resistant crops.

"Normally, plants put effort into growth and development," said University of Missouri Associate Professor Shuqun Zhang. "However, when plants sense pathogens, they have to use some of their energy and resources to make secondary metabolites to fight disease. Until now, very little has been known about how this process is regulated."

The study says plants sense the attack of a pathogen and activate defense responses by triggering a complex signaling cascade. One of the defense responses is the induction and accumulation of anti-microbial defense chemicals, known as phytoalexins.

Zhang found the specific signaling path, known as a mitogen-activated protein kinase cascade, ends when the defense chemical camalexin is created. Camalexin is essential for resistance to some plant diseases.

"By understanding at the molecular and cellular levels how plants protect themselves under adverse environmental conditions, such as pathogen attacks, we could eventually improve the disease resistance of crops," Zhang said.

The study appears in the early online edition of the Proceedings of the National Academy of Sciences.

Copyright 2008 by United Press International.