Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Plant immunity: PUBs are bad for the health

22.12.2008
Genes known as pubs have a negative effect on a plant’s immune system

Disease-causing pathogens carry unique molecular motifs that can be recognized by plants. The motifs, known as pathogen-associated molecular patterns or PAMPs, trigger several reactions in the plant which together generate a defensive immune response.

Ken Shirasu and co-workers at the RIKEN Plant Science Center, Yokohama, and the John Innes Centre, Norwich, UK, have discovered a triplet of genes that appear to hinder the PAMP immune response in Arabidopsis plants (1). The genes, called pub22, pub23 and pub24, code for enzymes called ubiquitin ligases (PUBs), which help to mark other proteins by attaching them to the universal protein ubiquitin.

The researchers decided to study the pub genes because they are similar to a gene known to promote disease resistance in tobacco. To their surprise, they found that when the three genes were deactivated in a mutant strain of Arabidopsis, the plant’s immune response improved. This means that the genes have a negative effect on immunity.

One of the first immune responses triggered by exposure to PAMPs is the oxidative burst, a rapid production of reactive oxygen compounds. In the mutant Arabidopsis plants, the oxidative burst was much stronger, and lasted longer than in wild-type plants. The mutants also showed prolonged activity of signaling molecules and genes known to improve the immune response, and more controlled cell death at infected sites.

These immune system enhancements are not specific to one type of pathogen—they occurred in response to several PAMP stimuli taken from bacterial flagella, the cell walls of fungi, and bacterial DNA transcription proteins. Even more impressively, the absence of pub genes hinders the pathogens themselves. Bacteria and moulds attacking the mutant plants showed up to 30 times less growth than on wild-type plants.

It is likely that the PUB enzymes break down or block the activity of other molecules that promote immunity, by binding the molecules to ubiquitin. A similar phenomenon has been observed in mammals, where ubiquitination has a detrimental effect on protein signaling.

In the future, the researchers hope to identify the exact molecules that are targeted by the PUB triplet. This could help to solve the biggest mystery—why plants have retained genes that make them more vulnerable to disease.

“Plants face pathogens every day and need appropriate levels of immune responses, so they don’t waste energy,” explains Shirasu. “Our knowledge of these regulatory genes could improve disease resistance in agriculture, especially when crops are transferred long distances to areas where they encounter completely new pathogens."

Reference

1. Trujillo, M., Ichimura, K., Casais, C. & Shirasu, K. Negative regulation of PAMP-triggered immunity by an E3 ubiquitin ligase triplet in Arabidopsis. Current Biology 18, 1396–1401 (2008).

The corresponding author for this highlight is based at the RIKEN Plant Immunity Research Team

Saeko Okada | ResearchSEA
Further information:
http://www.rikenresearch.riken.jp/research/605/
http://www.researchsea.com

More articles from Life Sciences:

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

nachricht Tiny Helpers that Clean Cells
14.08.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau

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

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

14.08.2018 | Life Sciences

Tiny Helpers that Clean Cells

14.08.2018 | Life Sciences

Algorithm provides early warning system for tracking groundwater contamination

14.08.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>