Navigation Links
When under attack, plants can signal microbial friends for help
Date:10/17/2008

Researchers at the University of Delaware have discovered that when the leaf of a plant is under attack by a pathogen, it can send out an S.O.S. to the roots for help, and the roots will respond by secreting an acid that brings beneficial bacteria to the rescue.

The finding quashes the misperception that plants are "sitting ducks"--at the mercy of passing pathogens--and sheds new light on a sophisticated signaling system inside plants that rivals the nervous system in humans and animals.

The research was led by Harsh Bais, assistant professor of plant and soil sciences at UD, former postdoctoral researcher Thimmaraju Rudrappa, who is now a research scientist at the DuPont Co., Kirk Czymmek, associate professor of biological sciences and director of UD's Bio-Imaging Center, and Paul Par, a biochemist at Texas Tech University.

The study is reported in the November issue of Plant Physiology and also is featured on the journal's cover. Rudrappa is the lead author of the research paper.

"Plants are a lot smarter than we give them credit for," says Bais from his laboratory at the Delaware Biotechnology Institute.

"People think that plants, rooted in the ground, are just sitting ducks when it comes to attack by harmful fungi or bacteria, but we've found that plants have ways of seeking external help," he notes.

In a series of laboratory experiments, the scientists infected the leaves of the small flowering plant Arabidopsis thaliana with a pathogenic bacterium, Pseudomonas syringae. Within a few days, the leaves of the infected plants began yellowing and showing other symptoms of disease.

However, the infected plants whose roots had been inoculated with the beneficial microbe Bacillus subtilis were perfectly healthy.

Farmers often add B. subtilis to the soil to boost plant immunity. It forms a protective biofilm around plant roots and also has antimicrobial properties, according to Bais.

Using molecular biological tools, the scientists detected the transmission of a long-distance signal, a "call for help," from the leaves to the roots in the plants that had Bacillus in the soil. The roots responded by secreting a carbon-rich chemical--malic acid.

All plants biosynthesize malic acid, Bais explains, but only under specific conditions and for a specific purpose--in this case, the chemical was actively secreted to attract Bacillus. Magnified images of the roots and leaves showed the ratcheted-up defense response provided by the beneficial microorganisms.

Czymmek captured the definitive proof using a state-of-the-art LSM 510 DUO laser scanning confocal microscope in UD's Bio-Imaging Center. UD is among only a few universities that own one of these million-dollar instruments.

"A plant is a challenge to image because at least half of it is below ground in the form of roots," Czymmek notes. "Here at UD, we use modern technologies including hydroponic growth systems with see-through chambers and sophisticated optical techniques that will enhance the image clarity when visualizing plants and the pathogens attacking them."

Bais and his colleagues are now working to determine what the aerial signal is from the infected leaf to the root using different pathogen-associated molecular markers (PAMPs).

The research not only sheds light on the remarkable signaling system in plants, but also is important to understand how invasive plants conquer new territory with the aid of plant microbes.

"Plants can't move from where they are, so the only way they can accrue good neighbors is through chemistry," Bais notes.


'/>"/>

Contact: Tracey Bryant
tbryant@udel.edu
302-831-8185
University of Delaware
Source:Eurekalert  

Related biology news :

1. Caltech scientists engineer supersensitive receptor, gain better understanding of dopamine system
2. NJIT professors research suggests changes in underwater data communications
3. Proteins in sperm unlock understanding of male infertility says new study
4. The dietary supplement genistein can undermine breast cancer treatment
5. Iron-moving malfunction may underlie neurodegenerative diseases, aging
6. Hidden infections crucial to understanding, controlling disease outbreaks
7. Better understanding of blood vessel constrictor needed to harness its power for patients
8. Pictures of hot fudge sundaes arouse: Understanding emotions improves our food choices
9. University of Miami scientist uncovers miscalculation in geological undersea record
10. Major European program for the environment under the spotlight in Lille, France
11. US Air Force technology helps scientists understand plant root function
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
When under attack, plants can signal microbial friends for help
(Date:2/7/2017)... , Feb. 7, 2017   MedNet Solutions , ... entire spectrum of clinical research, is pleased to announce ... , its innovative, highly flexible and award winning eClinical ... customers. iMedNet is a proven Software-as-a-Service (SaaS) ... Data Capture (EDC), but also delivers an entire suite ...
(Date:2/6/2017)... According to Acuity Market Intelligence, ongoing ... to continue to embrace biometric and digital identification ... Border Control (ABC) eGates and 1436 Automated Passport ... 163 ports of entry across the globe. Deployments ... combined CAGR of 37%. APC Kiosks reached 75% ...
(Date:2/2/2017)...   TapImmune, Inc. (NASDAQ: ... the development of innovative peptide and gene-based immunotherapeutics ... metastatic disease, announced today it has successfully completed ... second clinical lot of TPIV 200, the company,s ... manufactured vaccine product will be used to supply ...
Breaking Biology News(10 mins):
(Date:2/24/2017)... 24, 2017 Symic Bio, a biopharmaceutical company ... category of therapeutics, announced today the completion of enrollment ... artery disease. The trial will evaluate the safety and ... the reduction of restenosis following angioplasty. ... for SB-030," said Nathan Bachtell , M.D., Chief ...
(Date:2/24/2017)... Blood Corporation (NYSE: CO ) ("CCBC" or ... laboratory testing, hematopoietic stem cell processing and stem cell ... the third quarter and first nine months of fiscal ... Quarter of Fiscal 2017 Highlights Revenues ... 18.6% to RMB200.9 million ($28.9 million). ...
(Date:2/24/2017)... 23, 2017 China Biologic Products, Inc. (NASDAQ: CBPO) ... biopharmaceutical company in China, today announced its financial results for ... Fourth Quarter 2016 Financial Highlights ... 21.7% in RMB terms, or increased by 13.6% in USD ... quarter of 2015. Gross profit increased by ...
(Date:2/24/2017)... 24, 2017  OncoSec Medical Incorporated ("OncoSec") (NASDAQ: ONCS), ... a Key Opinion Leader event to highlight new clinical ... poster presentation at the upcoming 2017 ASCO-SITC Immuno-Oncology Symposium ... will be held in-person and via live webcast on ... AM PST at the Lotte New York Palace Hotel ...
Breaking Biology Technology: