Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Virus rounds up enzymes, disarms plant

02.06.2014

University of Tokyo researchers have described how a plant-virus protein suppresses an important plant defense mechanism that remembers viral genetic information, providing a new target for developing the first-ever chemical against plant viruses that globally cause more than $60 billion of crop losses each year.

Invading viruses carry genetic material that hijacks the host cell's machinery, fooling it into producing proteins and new viruses. All cells from fungi to plants and mammals employ RNA silencing, a cellular process essential for the regulation of gene expression that also functions as an important defense mechanism.


This is a model depicting that plant virus proteins (TGBp1: blue) aggregate and inactivate double-stranded RNA (dsRNA) synthesizing protein complexes (yellow: SGS3/RDR6 bodies).

Credit: Shigetou Namba, The University of Tokyo

Through RNA silencing, plant cells recognize this viral genetic material, remember and copy it so that other cells in the organism can be warned and destroy the virus. Viruses are known to fight back with RNA silencing suppressors, proteins that inhibit this defense mechanism, but how they interfere with the recording of viral genetic information was unknown.

Now, a research team headed by Professor Shigetou Namba and Dr. Yukari Okano in the Graduate School of Agricultural and Life Sciences has shown for the first time that the plant virus protein TGBp1 disarms RNA silencing by causing two enzymes involved in producing copies of viral genetic information to aggregate as inactive clusters in cells surrounded by the virus protein.

The two enzymes are SGS3 and RDR6, which are involved in producing copies of viral genetic information as double-stranded RNA, an essential step in the plant defense process. The researchers demonstrated that TGBp1 interacted with and inhibited the functions of SGS3 and RDR6, and attached fluorescent markers to TGBp1 and SGS3 to show visually that SGS3, which is usually distributed throughout the cell, formed clusters surrounded by TGBp1.

These results suggest that TGBp1 causes the enzymes SGS3 and RDR6 to form clusters, impeding the formation of double-stranded RNA and inhibiting the recording of viral genetic information, thus reducing plant resistance to viral infection.

"We expected that recording viral genetic information would be the most important step in RNA silencing, because if you can't remember the virus, you can't warn the rest of the organism and stop it spreading," explains Professor Namba.

"This would also make it important for the virus to target, but no one had confirmed any viral RNA silencing suppressors targeting this step in plants. Now we are very excited to be the first to do so, and we expect that other plant viral proteins will be found to have similar functions. Recently other researchers have reported that some viruses infecting humans also have RNA silencing suppressors, so this research may also contribute to the development of medicines targeting those viruses."

###

Keywords: RNA silencing, RNA silencing suppressor, double-stranded RNA, plant virus, TGBp1, SGS3, RDR6, plantago asiatica mosaic virus

Article information

Yukari Okano, Hiroko Senshu, Masayoshi Hashimoto, Yutaro Neriya, Osamu Netsu, Nami Minato, Tetsuya Yoshida, Kensaku Maejima, Kenro Oshima, Ken Komatsu, Yasuyuki Yamaji and Shigetou Namba, "In planta recognition of a dsRNA synthesis protein complex by a potexviral RNA silencing suppressor" The Plant Cell 26 (5) May 2014. doi: 10.1105/tpc.113.120535

http://www.plantcell.org/content/early/2014/05/30/tpc.113.120535.abstract

Links

The University of Tokyo
http://www.u-tokyo.ac.jp/en/

Graduate School of Agricultural and Life Sciences
http://www.a.u-tokyo.ac.jp/english/

Laboratory of Plant Pathology
http://papilio.ab.a.u-tokyo.ac.jp/planpath/en/index-en.html

Contact information

Research contact:

Professor Shigetou Namba
Laboratory of Plant Pathology
Graduate School of Agricultural and Life Sciences
The University of Tokyo
1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657
Tel: +81 (0)3-5841-5053
Fax: +81 (0)3-5841-5054
Email: anamba@mail.ecc.u-tokyo.ac.jp

Press officer:

Yoko Takemoto
Public Relations Division
The University of Tokyo
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654
Tel: +81 (0)3-5841-2031
Fax: +81 (0)3-3816-3913
Email: kouhoukikaku@ml.adm.u-tokyo.ac.jp

Yoko Takemoto | Eurek Alert!

Further reports about: Agricultural Pathology RNA Virus clusters copies enzymes silencing suppressor viruses

More articles from Life Sciences:

nachricht Pathogenic bacteria hitchhiking to North and Baltic Seas?
22.07.2016 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Unconventional quasiparticles predicted in conventional crystals
22.07.2016 | Max-Planck-Institut für Chemische Physik fester Stoffe

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Mapping electromagnetic waveforms

Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.

Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...

Im Focus: Continental tug-of-war - until the rope snaps

Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases

Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...

Im Focus: A Peek into the “Birthing Room” of Ribosomes

Scaffolding and specialised workers help with the delivery – Heidelberg biochemists gain new insights into biogenesis

A type of scaffolding on which specialised workers ply their trade helps in the manufacturing process of the two subunits from which the ribosome – the protein...

Im Focus: New protocol enables analysis of metabolic products from fixed tissues

Scientists at the Helmholtz Zentrum München have developed a new mass spectrometry imaging method which, for the first time, makes it possible to analyze hundreds of metabolites in fixed tissue samples. Their findings, published in the journal Nature Protocols, explain the new access to metabolic information, which will offer previously unexploited potential for tissue-based research and molecular diagnostics.

In biomedical research, working with tissue samples is indispensable because it permits insights into the biological reality of patients, for example, in...

Im Focus: Computer Simulation Renders Transient Chemical Structures Visible

Chemists at the University of Basel have succeeded in using computer simulations to elucidate transient structures in proteins. In the journal Angewandte Chemie, the researchers set out how computer simulations of details at the atomic level can be used to understand proteins’ modes of action.

Using computational chemistry, it is possible to characterize the motion of individual atoms of a molecule. Today, the latest simulation techniques allow...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

GROWING IN CITIES - Interdisciplinary Perspectives on Urban Gardening

15.07.2016 | Event News

SIGGRAPH2016 Computer Graphics Interactive Techniques, 24-28 July, Anaheim, California

15.07.2016 | Event News

Partner countries of FAIR accelerator meet in Darmstadt and approve developments

11.07.2016 | Event News

 
Latest News

Hey robot, shimmy like a centipede

22.07.2016 | Information Technology

New record in materials research: 1 terapascals in a laboratory

22.07.2016 | Physics and Astronomy

University of Graz researchers challenge 140-year-old paradigm of lichen symbiosis

22.07.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>