News Release 05-034
Roots Engage in Underground Chemical Warfare
Cells secrete substances to fight bacterial invaders
Arabidopsis thaliana roots secrete antimicrobial compounds to ward off bacterial pathogens.
March 9, 2005
This material is available primarily for archival purposes. Telephone numbers or other contact information may be out of date; please see current contact information at media contacts.
In addition to providing physical support and taking in nutrients, plant roots secrete a wide variety of compounds that affect other nearby roots, as well as insects and microbes. But because it goes on unseen, bactericidal root activity has not been extensively investigated—until now. Using the model plant Arabidopsis thaliana, a relative of garden-variety cabbage, Jorge Vivanco and co-workers at Colorado State University, together with Frederick Ausubel at Harvard Medical School, demonstrated that “root exudates” contain antimicrobial agents that ward off the continual attacks by soil pathogens.
The work is published in the March 10 issue of the journal Nature.
The exudates from Arabidopsis roots kill a wide range of bacteria, confirming that roots are not always vulnerable, anchored targets. The natural production of these antimicrobial chemicals offers one explanation for why so few bacteria types actually cause disease in plants. Of the more than 50,000 plant diseases occurring in the United States, fungal pathogens are the leading cause.
“Current understanding of plant defenses does not readily explain why a pathogen can cause disease in one plant species and not another,” says Vivanco. “Our findings will help researchers solve the mysteries of plant disease and immunity.”
In these experiments, however, root exudates did not kill all of the tested strains of bacteria. One particular strain of Pseudomonas syringae, a bacterium that causes disease in both tomatoes and Arabidopsis, has a seemingly fail-safe mechanism to overcome the plant’s defenses. The bacterium not only survives exposure to the antimicrobial substances, it also blocks the plant's ability to produce them.
Both Vivanco and Ausubel are supported by separate awards from the division of Molecular and Cellular Biosciences at the National Science Foundation (NSF).
Vivanco is a recipient of NSF’s prestigious Faculty Early Career Development Award (CAREER). CAREER awards support the early career development of those researcher-educators who are deemed most likely to become the academic leaders of the 21st century. Parag Chitnis, the NSF program manager of Vivanco’s award said, “This work is an exciting outcome of a bold and challenging project. The work paves the way to understand and combat crop diseases.”
The program manager for Ausubel’s award, Michael Mishkind said, “The puzzle of why so few bacterial species are pathogens remains a fascinating problem. The simple, yet elegant experimental approaches used by this team uncovered a critical aspect of the battle that occurs between plants and microbes.”
-NSF-
Media Contacts
Randy Vines, NSF, (703) 292-8070, email: rvines@nsf.gov
Program Contacts
Parag Chitnis, NSF, (703) 292-7132, email: pchitnis@nsf.gov
Michael L. Mishkind, NSF, (703) 292-7190, email: mmishkin@nsf.gov
Principal Investigators
Jorge Vivanco, Colorado State University, (970) 491-7170, email: jvivanco@colostate.edu
The U.S. National Science Foundation propels the nation forward by advancing fundamental research in all fields of science and engineering. NSF supports research and people by providing facilities, instruments and funding to support their ingenuity and sustain the U.S. as a global leader in research and innovation. With a fiscal year 2023 budget of $9.5 billion, NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and institutions. Each year, NSF receives more than 40,000 competitive proposals and makes about 11,000 new awards. Those awards include support for cooperative research with industry, Arctic and Antarctic research and operations, and U.S. participation in international scientific efforts.
Connect with us online
NSF website: nsf.gov
NSF News: nsf.gov/news
For News Media: nsf.gov/news/newsroom
Statistics: nsf.gov/statistics/
Awards database: nsf.gov/awardsearch/
Follow us on social
Twitter: twitter.com/NSF
Facebook: facebook.com/US.NSF
Instagram: instagram.com/nsfgov