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 Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>