Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study: Plants use dual defense system to fight pathogens

03.06.2005


Researchers have uncovered the link between two biochemical pathways that plants use to defend themselves against pathogens – pathways that scientists have long believed worked independently of each other.



Knowing how these pathways of immunity work may one day help researchers breed plants that can better resist a variety of pathogens, said David Mackey, the study’s lead author and an assistant professor of horticulture and crop science at Ohio State University .

He and his colleagues explain their findings in the current issue of the journal Cell.


The researchers infected Arabidopsis plants with a bacterial strain of Pseudomonas syringae, a bacterium that usually infects tomato crops. Both Arabidopsis, a plant of the mustard family, and P. syringae are models that researchers commonly use to conduct basic plant research.

One of the immune pathways that interested the researchers recognizes what they call pathogen-associated molecular patterns, or PAMPs. The PAMP pathway appears to be a plant’s first line of defense against pathogenic attackers.

“The PAMP path induces a fairly weak immune response,” Mackey said. “Even so, there is growing evidence that suggests these kinds of responses are extremely important in restricting the growth of many pathogens.”

The other pathway uses disease-resistant proteins, or R-proteins, which can detect certain molecules, called effectors, that are secreted by pathogens. This pathway produces a stronger immune response than the PAMP pathway, Mackey said.

He and his colleagues found that the R-protein pathway steps in when PAMP is rendered useless by a pathogen.

Certain types of bacteria, including P. syringae, make a hypodermic needle-like structure that pierces the outermost membrane of a healthy plant or animal cell. The pathogen uses this conduit to send infectious effector proteins into the host cell.

While P. syringae injects about 40 different varieties of effector molecules into a plant cell, the researchers focused on the actions of two of these molecules – AvrRpt2 and AvrRpm1. Both target a protein key to Arabidopsis health­.

The scientists found that both of these effector molecules effectively shut down the PAMP pathway. But the plant’s R-proteins detect this, and come to the rescue.

“The R-proteins detect the insidious activity by which the pathogen’s effectors block the PAMP pathway,” Mackey said. “PAMP defense responses are probably often effective, but they may be blocked by the pathogen’s effector proteins. If an R-protein recognizes a pathogen’s presence, it usually induces a very strong immune response, in most cases stopping a would-be infection.

“This work further suggests that plants use an active, complex immune system to combat pathogens,” he said. “They have complicated surveillance systems that detect various infection-causing molecules and trigger defensive responses.”

A next step in this line of work is to look at other pathogen effector proteins and analyze their role in causing infections.

Mackey conducted the study with Ohio State colleagues Min Gab Kim, a graduate student in the department of plant cellular and molecular biology, and graduate student Luis da Cunha and post-doctoral fellow Aidan McFall, both in the department of horticulture and crop science; Youssef Belkhadir and Jeffrey Dangl, both with the department of biology at the University of North Carolina, Chapel Hill; and Sruti DebRoy, formerly of the U.S. Department of Energy Plant Research Laboratory at Michigan State University.

Funding for this work came from the National Science Foundation and the NSF’s Arabidopsis Project; Ohio State’s Ohio Agricultural and Research Development Center; and the U.S. Department of Energy.

| EurekAlert!
Further information:
http://www.osu.edu

More articles from Studies and Analyses:

nachricht Do microplastics harbour additional risks by colonization with harmful bacteria?
05.04.2018 | Leibniz-Institut für Ostseeforschung Warnemünde

nachricht Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>