Corporate Banner
Satellite Banner
AgriGenomics
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

New African Cassava Resists Devastating Viruses

Published: Tuesday, October 02, 2012
Last Updated: Tuesday, October 02, 2012
Bookmark and Share
Plant scientists at ETH Zurich have developed a new African cassava preferred by consumers and farmers that is resistant to the two major virus diseases in Africa. Now they want to test the resistant cassava in Africa.

Cassava is one of the most important crops in tropical countries, particularly in Sub-Saharan Africa. However, plant viruses are threatening cassava production and with it the staple food of hundreds of millions of people. Under the leadership of Wilhelm Gruissem, Professor of Plant Biotechnology and his senior scientist Dr. Hervé Vanderschuren, researchers at ETH Zurich have used gene technology to develop a new cassava variety that is resistant to the feared cassava brown streak virus. The virus infects the edible starchy roots and turns them brown, which makes the roots unpalatable for consumers. The virus originated in East Africa and is threatening to spread to Central and West Africa.

Developing immune cassava using small RNAs

In order to make cassava resistant to the brown streak virus, the researchers modified the genetic make-up of one variety of cassava to produce small interfering RNA molecules (siRNA). The plant produces the siRNA naturally after virus infection, but the researchers have now tricked cassava to produce the siRNA in all of its parts before the virus can infect it. As soon as the virus attacks the plant, the short siRNA stops the virus by attaching to the genome of the virus that is also made of RNA. This prevents the virus from multiplying and spreading throughout the plant.

Glasshouse trials have shown that the new gene producing the siRNA protects cassava effectively from the virus. Even several months after infection of the transgenic cassava plants with the brown streak virus, the scientists did not find any evidence that the virus could multiply. The production of the siRNA does not affect cassava itself. It grows normally and produces healthy roots. The researchers targeted a part of the virus RNA genome that has been highly conserved during evolution and thus only very rarely changes. This should make it more difficult for the virus to adapt to the siRNA-mediated immunity.

Resistance to another cassava virus remains

The researchers used the Nigerian TME 7 variety, also known as “Oko-iyawo”. This variety is naturally resistant to cassava mosaic disease, which is caused by another virus that is severely impacting cassava production all of Africa. Prof. Wilhelm Gruissem explains that this resistance is not changed by the new resistance to the brown streak virus. The brown streak virus is most likely transmitted by the same silverleaf whitefly (Latin: Bemisia tabaci) that also spreads cassava mosaic disease. This tiny insect sucks on plant juices, and in doing so transmits the viruses into the cassava plant. The silverleaf whitefly population has hugely increased in recent decades, emphasises Prof. Willhelm Gruissem, and is posing a greater threat than ever to the growth of cassava. He adds that it is difficult to control the whitefly, even if African farmers can afford to buy insecticides. This is why it is much more efficient and more environmentally friendly to protect cassava against viruses using genetic modification.

Preferred variety extended

The ETH Zurich scientists chose TME 7 from dozens of potential varieties because TME 7 is popular among consumers and farmers and has the best prerequisites for successful cultivation. As the next step, Prof. Gruissem and Dr. Vanderschuren, together with colleagues in Africa, want to test if the improved cassava variety in the field remains resistant to both viruses under natural conditions. The Fiat Panis Foundation in Germany, which has supported cassava research at ETH, has already reserved funding for field experiments. The ETH Zurich scientists are also actively engaged in transferring the technology to interested research institutes in Africa to develop virus resistance in local varieties preferred by consumers in their countries.


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,900+ scientific posters on ePosters
  • More than 4,200+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Swiss researchers develop rice with increased (six-fold!) iron content
Scientists at ETH Zurich have developed rice plants that contain six times more iron in polished rice kernels.
Thursday, August 20, 2009
Scientific News
New Method Promises to Speed Development of Food Crops
A new study addresses a central challenge of transgenic plant development: how to reliably evaluate whether genetic material has been successfully introduced.
Where Cancer Cells May Begin
Scientists use fruit fly genetics to understand how things could go wrong in cancer.
Key Enzyme in Pierce’s Disease Grapevine Damage Uncovered
UC Davis plant scientists have identified an enzyme that appears to play a key role in the insect-transmitted bacterial infection of grapevines with Pierce’s disease, which annually costs California’s grape and wine industries more than $100 million.
Bacteria Attack Lignin with Enzymatic Tag Team
Team from Rice, University of Wisconsin-Madison shows how nature handles lignin.
Milestone Resource in Wheat Research Now Available for Download
Leading on from The Genome Analysis Centre’s (TGAC) previous announcement of their new bread wheat genome assembly, the landmark resource is now publically available to download at the European Bioinformatics Institute’s (EMBL-EBI) Ensembl database for full analysis.
Nano-Reactor for the Production of Hydrogen Biofuel
Combining bacterial genes and virus shell creates a highly efficient, renewable material used in generating power from water.
Cleaning Wastewater with Pond Scum
A blob of algae scooped from a fountain on South Street almost two years ago, has seeded a crop of the green stuff that Drexel University researchers claim is more effective at treating wastewater than many of the processes employed in municipal facilities today.
Global Reductions in Mercury Emissions Should Lead to Billions in Economic Benefits for U.S.
Benefits from international regulations may double those of domestic policy.
A Worm with Five Faces
Max Planck scientists discover new roundworm species on Réunion.
A Gene for New Species is Identified
A University of Utah-led study identified a long-sought “hybrid inviability gene” responsible for dead or infertile offspring when two species of fruit flies mate with each other.
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,900+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,200+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!