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 Fine organic particles in the atmosphere are more often solid glass beads than liquid oil droplets
21.04.2017 | Max-Planck-Institut für Chemie

nachricht Study overturns seminal research about the developing nervous system
21.04.2017 | University of California - Los Angeles Health Sciences

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>