Weve identified a key molecular pathway within plant cells, says scientist Jen Sheen of the molecular biology department at Massachusetts General Hospital (MGH), who authored the Nature paper with several of her colleagues. If we activate this pathway in leaves, weve found that we can make them more resistant to pathogens like bacteria and fungi.

Adds Jane Silverthorne, program director in NSFs biological sciences directorate, This is an exciting step forward. For the first time, we have a detailed description of an important plant signaling pathway. This information will bevaluable to furthering our understanding of basic signaling mechanisms in plants, as well as for developing crops with improved resistance to pathogens."

Sheen says plants have an effective and sophisticated immune system. Their first line of defense is a thick cell wall covered with cuticle layers that acts somewhat like human skin. If a pathogen is able to penetrate this physical barrier, for example through a wound, the pathogen will usually be detected by receptors on the surface or inside of the plant cells. One of the best characterized pathogen receptors has a feature characteristic of other plant receptors known as a Leucine-rich repeat (LRR) receptor kinase. This receptor kinase can recognize a structure on bacterial pathogens called flagellin that makes the bacteria motile.

Theres a conserved region in the flagellin thats present on a wide range of bacterial pathogens, so plants are very effective at detecting pathogens. Highlighting the conservation and similarity of immune systems in plants and animals, bacterial flagellin can a
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Contact: Cheryl Dybas
cdybas@nsf.gov
703-292-8070
National Science Foundation
27-Feb-2002