"Contrary to what we thought we'd find, our experiments showed that at least three different proteins work in concert with one another in tug-of war or teeter totter-fashion to keep plant defenses in a state of constant readiness," said Dr. Jeffrey L. Dangl, John N. Couch professor of biology in UNC's College of Arts and Sciences.
Previously, he and others believed that the proteins -- RAR1, SGT1 and HSP90 -- were required for what is called signal transduction -- relaying like Paul Revere the message that an enemy had arrived, Dangl said. Instead, they are needed to form an even earlier disease surveillance antenna or hair trigger. When disease invaders pull that trigger, infected plants cells quickly commit suicide, often preventing the invader from destroying the entire plant.
The new discovery appears to be a universal mechanism for defense by all plants against not only bacteria and viruses, but also parasitic fungi, insects and worms, he said.
"This work is important because every year, these organisms cause us to lose some 30 percent of our grain, fruit and vegetable crops after all the human, water and soil energy has already gone into producing them," Dangl said. "The hope is that we might be able to manipulate plants' immune systems to make them more resistant to pathogens using fewer expensive and polluting chemicals."
A report on the findings appears in this week's edition (June 24) of Science Express, the online, early-release version of the journal Science. Other authors are postdoctoral fellow Dr. Ben F. Holt III and Ph.D. student Youssef Belkhadir, both in biology.
"Plants use resistance proteins to defend themselves against pathogen attack b