How plants fight diseasesPublished On: Tue, Mar 29th, 2011 | Plant Sciences | By BioNews
Scientists have shed new light on how plants fight diseases caused by bacterial pathogens.
Wenbo Ma, a young plant pathologist at the University of California, Riverside, has performed research on the soybean plant in the lab that makes major inroads into our understanding of plant-pathogen interactions, a rapidly developing area among the plant sciences.
Her breakthrough research can help scientists come up with effective strategies to treat crops that have succumbed to disease or, when used as a preventative measure, to greatly reduce their susceptibility to disease.
Ma, an assistant professor of plant pathology and microbiology, and her colleagues showed that the bacterial pathogens target isoflavones, a group of compounds in plant cells that defend the plant from bacterial infection, resulting in a reduction in isoflavone production.
First, the pathogens inject virulence bacterial proteins, called HopZ1, through needle-like conduits into the plant cells. These proteins then largely reduce the production of the isoflavones and promote disease development.
However, by sensing the presence of HopZ1, the plants mount a robust resistance against the pathogen, including the production of a very high amount of isoflavones. At this point, the pathogen must come up with new strategies by either changing the kind of proteins it injects into the plant, not injecting any proteins at all, or injecting virulence proteins in a way that helps them escape detection by the plant. In this way, the virulence bacterial proteins and the plant host engage in an endless “arms race.”
“Some scientists have shown that these proteins block signaling transduction pathways in the plant, which eventually weakens plant immunity. We are introducing a fresh perspective on this topic, namely, that the pathogens evolved strategies to directly attack the production of plant antimicrobial compounds, such as isoflavones, thus compromising the plant”s defense mechanism,” said Ma.
The study has been published in the journal Cell Host and Microbe.