Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

In evolutionary arms race, a bacterium is found that outwits tomato plant's defenses

20.07.2007
An arms race is under way in the plant world. It is an evolutionary battle in which plants are trying to beef up their defenses against the innovative strategies of pathogens. The latest example of this war is a bacterium (Pseudomonas syringae) that infects tomatoes by injecting a special protein into the plant's cells to undermine the plant's defense system.

"Plant breeders often find that five or six years after their release, resistant plant varieties become susceptible because pathogens can evolve very quickly to overcome plant defenses," said Gregory Martin, Cornell professor of plant pathology, a scientist at the Boyce Thompson Institute for Plant Research (BTI) on the Cornell campus and the senior author of the research paper, published in the July 19 issue of the journal Nature. "However, every now and then, breeders develop a plant variety that stays resistant for 20 years or more."

Understanding why some varieties have more durable disease resistance is important to the development of more sustainable agricultural practices, he said.

The study by Cornell and BTI scientists describes how a single bacterial protein, AvrPtoB, which is injected by P. syringae into plant cells through a kind of molecular syringe, can overcome the plant's resistance. Normally, the plant's defense system looks out for such pathogens and, if detected, mounts an immune response to stave off disease. As part of this surveillance system, tomatoes carry a protein in their cells called Fen that helps detect P. syringae and trigger an immune response.

... more about:
»AvrPtoB »FEN »Pathogen »bacterium »plant' »syringae »tomato

But some strains of P. syringae have evolved the AvrPtoB protein that mimics a tomato enzyme known as an E3 ubiquitin ligase, which tags proteins to be destroyed. Once injected, AvrPtoB binds the Fen protein, and the plant's own system eliminates it, allowing the bacteria to avoid detection and cause disease.

"This paper explains how a pathogen can evolve to escape detection," said lead author Tracy Rosebrock, a graduate student in Cornell's Department of Plant Pathology and BTI. "The bacterium has one specific protein that it uses to turn off the plant's immunity."

The researchers found that the Fen gene is present in both cultivated tomatoes and many wild tomato species, leading them to believe that the gene is likely ancient in origin and that many members of the tomato family have used it to resist P. syringae infections over the years. Since the Fen protein still detects AvrPtoB-like proteins from some strains of P. syringae, prompting an effective immune response, the researchers believe new P. syringae strains have only recently evolved a version of AvrPtoB that includes an E3 ubiquitin ligase enzyme that interferes with the plant's surveillance.

"This paper provides molecular data that supports the evolutionary 'arms race' theory" that as pathogens develop new ways to spread and attack organisms, the organisms in turn create novel defenses, each in a continuous battle to outdo the other, said Rosebrock.

The research was funded by the National Institutes of Health, the National Science Foundation and the Triad Foundation, a private charitable trust.

Blaine Friedlander | EurekAlert!
Further information:
http://www.cornell.edu

Further reports about: AvrPtoB FEN Pathogen bacterium plant' syringae tomato

More articles from Life Sciences:

nachricht During HIV infection, antibody can block B cells from fighting pathogens
14.08.2018 | NIH/National Institute of Allergy and Infectious Diseases

nachricht First study on physical properties of giant cancer cells may inform new treatments
14.08.2018 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

Im Focus: World record: Fastest 3-D tomographic images at BESSY II

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

'Building up' stretchable electronics to be as multipurpose as your smartphone

14.08.2018 | Information Technology

During HIV infection, antibody can block B cells from fighting pathogens

14.08.2018 | Life Sciences

First study on physical properties of giant cancer cells may inform new treatments

14.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>