Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Toxic Substances in Banana Plants Kill Root Pests

11.12.2013
Banana plants protect themselves from parasitic nematodes by increasing local concentrations of defensive substances in infected root tissues.

Bananas are a major food staple for about 400 million people in the tropical and subtropical regions of Asia, Africa and Latin America. However, banana yields worldwide are severely threatened by pests.


Few red, phenylphenalenone containing regions on the root of the resistant Yangambi km5 root within healthy root tissue (below) and massive root damage in the susceptible Grande Naine banana (above).

D. Hölscher / Max Planck Institute for Chemical Ecology


Microscopic image of the nematode Radopholus similis: Inside the roundworm the lipid droplets that store the toxin, phenylphenalenone anigorufone (yellow), are clearly visible.

S. Dhakshinamoorthy / University of Leuven, Belgium

Dirk Hölscher from the Max Planck Institute for Chemical Ecology in Jena, Germany, and an international team of researchers have discovered that some banana varieties accumulate specific plant toxins in the immediate vicinity of root tissue that has been attacked by the parasitic nematode Radopholus similis.

This local accumulation is crucial for the plant’s resistance to this pest organism. The toxin is stored in lipid droplets in the body of the nematode and the parasite finally dies. These findings provide important clues for the development of pest-resistant banana varieties. (Proceedings of the National Academy of Sciences USA, December 9; 2013, DOI 10.1073/pnas.1314168110)

Banana yields worldwide threatened by pests

Bananas are among the world’s most important food crops. Dessert bananas are produced primarily for homegrown consumption in China and India and for export to the northern hemisphere in Latin America. In Europe, they represent the most popular tropical fruit. Plantains (a type of cooking banana) are important components of daily meals in Africa and Southeast Asia. They are highly prized because of their high contents of nutrients, such as potassium, magnesium and vitamins B and C.

Apart from fungi and insects, the parasitic nematode Radopholus similis is considered a major banana pest. It attacks the roots of banana plants, causing slower growth and development of the plant and fruit. In the final stage of the disease plants topple over − often when already bearing an immature fruit bunch. Yield losses up to 75% can be the result of R. similis infestation. In order to control such pests in banana plantations, high doses of synthetic pesticides are used which not only cause ecological damage, but can also have severe negative effects on the health of people who are exposed to these chemicals.

Scientists at the Max Planck Institute for Chemical Ecology and their colleagues from universities in Leuven (Belgium), Jena, Kassel-Witzenhausen, Halle, Bonn and Bremen, as well as the Leibniz Institute for Natural Product Research and Infection Biology and the Leibniz Institute of Photonic Technology in Jena have now taken a closer look at the plant-nematode interactions in the context of resistance versus susceptibility. They compared two banana varieties, a resistant and a susceptible one, and studied their defense responses to Radopholus similis.

Phenylphenalenones: Local accumulation of defensive substances in infected regions of root tissues inhibits further propagation of the pest

The researchers used modern spectroscopic analysis and imaging techniques and were able to identify and localize defense substances in banana roots: The plants accumulated so-called phenylphenalenones only in infected regions of their roots, but not in healthy tissues. This was the case in both the resistant and the susceptible banana variety. The concentration of the most active compound anigorufone, however, was much higher in the immediate vicinity of lesions on the roots of resistant bananas in comparison to infected root tissues of the nematode susceptible banana plants. “The production of the toxin alone is not responsible for the banana plant’s resistance to nematodes. It is the differential concentration in specific regions of the roots, which is particularly high at the precise location of the nematode attack, which makes the difference and confers resistance. We measured far higher concentrations of the toxin in these localized regions in the resistant banana variety,” Dirk Hölscher summarizes the results.

Lipid droplets containing the active compounds visible in the nematode

The toxic effect of anigorufone and other substances was tested on living nematodes. It turned out that it was in fact anigorufone which was most toxic to the pest organism. By using imaging techniques, the researchers were able to visualize the plant toxin within the body of the roundworm. There the lipid-soluble anigorufone accumulated in lipid droplets which increased in size as they converged and finally killed the nematode. Why these complex lipid droplets are formed and why the nematodes cannot metabolize or excrete the toxin still needs to be clarified. However, it is likely that the growing lipid droplets displace the inner organs of the nematode causing an eventual metabolic dysfunction.

The scientists will now try to find out how resistant banana plants biosynthesize and translocate the defense compounds on a molecular level. Such insights will provide important clues for the development of banana varieties which are resistant to the nematodes. This could help to minimize the excessive use of highly toxic pesticides in banana plantations which jeopardize the environment and people’s lives. [AO]

Original Publication:
Hölscher, D., Dhakshinamoorthy, S., Alexandrov, T., Becker, M., Bretschneider, T., Bürkert, A., Crecelius, A. C., De Waele, D., Elsen, A., Heckel, D. G., Heklau, H., Hertweck, C., Kai, M., Knop, K., Krafft, C., Madulla, R. K., Matthäus, C., Popp, J., Schneider, B., Schubert, U., Sikora, R., Svatoš, A., Swennen, R. (2013). Phenalenone-type phytoalexins mediate resistance of banana plants (Musa spp.) to the burrowing nematode Radopholus similis. Proceedings of the National Academy of Sciences of the United States of America. DOI 10.1073/pnas.1314168110

http://dx.doi.org/10.1073/pnas.1314168110

Further Information:
Dr. Dirk Hölscher, Max Planck Institute for Chemical Ecology,
Tel. +49 3641 57-2551, E-Mail hoelscher@ice.mpg.de
Dr. Bernd Schneider, Max Planck Institute for Chemical Ecology,
Tel. +49 3641 57- 1600, E-Mail schneider@ice.mpg.de
Prof. Dr. Andreas Bürkert, University of Kassel-Witzenhausen,
Tel. +49 5542-98-1228, E-Mail buerkert@uni-kassel.de
Contact and Picture Requests:
Angela Overmeyer M.A., Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07743 Jena, Germany, Tel. +49 3641 57-2110, E-Mail overmeyer@ice.mpg.de

Angela Overmeyer | Max-Planck-Institut
Further information:
http://www.ice.mpg.de/ext/1055.html?&L=0
http://www.ice.mpg.de/ext/735.html

More articles from Agricultural and Forestry Science:

nachricht New data unearths pesticide peril in beehives
21.04.2017 | Cornell University

nachricht New rice fights off drought
04.04.2017 | RIKEN

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

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...

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

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>