RICHLAND, Wash. A common plant puts out a welcome mat to bacteria seeking to invade, and scientists have discovered the mat's molecular mix.
The study published this week in the Proceedings of the National Academy of Sciences reveals new targets during the battle between microbe and host that researchers can exploit to protect plants.
The team showed that the humble and oft-studied plant Arabidopsis puts out a molecular signal that invites an attack from a pathogen. It's as if a hostile army were unknowingly passing by a castle, and the sentry stood up and yelled, "Over here!" focusing the attackers on a target they would have otherwise simply passed by.
"This signaling system triggers a structure in bacteria that actually looks a lot like a syringe, which is used to inject virulence proteins into its target. It's exciting to learn that metabolites excreted by the host can play a role in triggering this system in bacteria," said Thomas Metz, an author of the paper and a chemist at the Department of Energy's Pacific Northwest National Laboratory.
The findings come from a collaboration of scientists led by Scott Peck of the University of Missouri that includes researchers from Missouri, the Biological Sciences Division at PNNL, and EMSL, DOE's Environmental Molecular Sciences Laboratory.
The research examines a key moment in the relationship between microbe and host, when a microbe recognizes a host as a potential target and employs its molecular machinery to pierce it, injecting its contents into the plant's cells a crucial step in infecting an organism.
The work focused on bacteria known as Pseudomonas syringae pv. tomato DC3000, which can ruin tomatoes as well as Arabidopsis. The bacteria employ a molecular system known as the Type 3 Secretion System, or T3SS, to infect plants. In tomatoes, the infection leads to unsightly brown spots.
Peck's team at the University of
|Contact: Tom Rickey|
DOE/Pacific Northwest National Laboratory