"Until now, we didn't really know exactly how the protein produced by this fungus was causing disease, whether it was from inside or outside of the plant cells," said Viola Manning, an OSU faculty research assistant and co-author of both publications. "No one had ever shown before that a protein could move, without a pathogen's assistance, from outside a plant cell to the inside. But in this case, the protein does penetrate the cell membrane and interacts with chloroplasts, ultimately leading to cell death."
The scientists said this mechanism probably will be found in other cells besides wheat, and with other proteins. And while it may lead ultimately to some way to help address this plant disease problem in wheat, the more important discovery is the new pathway into plant cells.
"We still don't know exactly how the protein penetrates the cell, but it's clear that it does," said Andrew Karplus, an OSU professor of biochemistry and biophysics. "And with work done by a graduate student, Ganapathy Sarma, we also now have a clear understanding of what the molecular structure of the toxin looks like. With continued research, we should not only be able to determine how the protein is getting into the cell, but also remove the toxic effect associated with it.
"What that would leave us with is a type of delivery vehicle, a completely new way to deliver compounds inside of a plant cell and target specific genes. This is a new and unprecedented insight into how plants can work."
The process of proteins getting inside of cells and affecting their behavior is common in animal cells, the scientists said. For instance, that's how the AIDS virus causes its damage. But the same process had never before been shown to exist in plant cells, which have been evolving separately from animals for hundreds of millions of years.
With a new delivery mechanism such as this, applied research could be don
Source:Oregon State University