Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 
Datenbankrecherche:

 

Fighting the Colorado potato beetle with RNA interference

27.02.2015

RNA interference protects potato plants against herbivore attack.

Colorado potato beetles are a dreaded pest of potatoes all over the world. Since they do not have natural enemies in most potato producing regions, farmers try to control them with pesticides. However, this strategy is often ineffective because the pest has developed resistances against nearly all insecticides.


Colorado potato beetle (CPB): On average 40 to 50 cm2 of leaf material are eaten by each of the beetles’ larvae. Infestation with CPB can result in crop losses up to 50 %, if there is no pest control.

©Sher Afzal Khan, Max Planck Institute for Chemical Ecology


Feeding experiment: Leaves of unmodified plants were compared to transplastomic leaves. Larvae were fed on these leaves for 3 days in intervals of 24 hours. Leaves were replaced after each interval.

©Sher Afzal Khan, Max Planck Institute for Chemical Ecology

Now, scientists from the Max Planck Institutes of Molecular Plant Physiology in Potsdam-Golm and chemical Ecology in Jena have shown that potato plants can be protected from herbivory using RNA interference (RNAi). They genetically modified plants to enable their chloroplasts to accumulate double-stranded RNAs (dsRNAs) targeted against essential beetle genes. (Science, February 2015).

RNA interference (RNAi) is a type of gene regulation that naturally occurs in eukaryotes. In plants, fungi and insects it also is used for protection against certain viruses. During infection, many viral pathogens transfer their genetic information into the host cells as double-stranded RNA (dsRNA). Replication of viral RNA leads to high amounts of dsRNA which is recognized by the host‘s RNAi system and chopped up into smaller RNA fragments, called siRNAs (small interfering RNAs). The cell then uses siRNAs to detect and destroy the foreign RNA.

But the RNAi mechanism can also be exploited to knock down any desired gene, by tailoring dsRNA to target the gene's messenger RNA (mRNA). When the targeted mRNA is destroyed, synthesis of the encoded protein will be diminished or blocked completely. Targeting an essential gene of a crop pest can turn dsRNA into a precise and potent insecticide.

Some crop plants have recently been engineered by modifying their nuclear genomes to produce dsRNA against certain insects. „This never resulted in full protection from herbivory“, says Ralph Bock of the Max Planck Institute of Molecular Plant Physiology, „because the plant's own RNAi system prevents the accumulation of sufficient amounts of dsRNA. We wanted to circumvent this problem by producing dsRNA in the chloroplasts instead“.

These organelles, which perform photosynthesis in green plants, are descendants of formerly free-living cyanobacteria, which are prokaryotes that lack an RNAi system. Presuming that chloroplasts would accumulate high amounts of dsRNA, the scientists in Ralph Bock's group decided to generate so-called transplastomic plants. In such plants, the chloroplast genome is the target of genetic modification instead of the nuclear genome.

To test this system on a real insect pest, the scientists chose the Colorado potato beetle. This little striped beetle was introduced into Europe accidentally at the end of the 19th century. Nowadays, it is a worldwide pest and can cause massive damage in agriculture. Besides potato leaves the adult beetle and its larvae also feed on other nightshade crops, like tomato, bell pepper and tobacco. The pest is difficult to control because of the widespread occurrence of insecticide resistance. „By using chloroplast transformation we generated potato plants that accumulate high amounts of long stable dsRNAs targeting essential genes in the beetle“, says Ralph Bock.

The efficacy of the dsRNAs as an insecticide was tested at the Max Planck Institute for Chemical Ecology in Jena. Larvae were fed on detached potato leaves and the mortality was monitored for nine days. The leaves were taken from transplastomic dsRNA plants, conventional transgenic dsRNA plants with a modified nuclear genome, and unmodified plants. For comparison, dsRNAs targeting two different genes were tested.

„Transplastomic leaves producing dsRNA against the actin gene caused a mortality rate of 100% after five days of feeding“, says Sher Afzal Khan from Jena. The actin gene encodes a structural protein that is essential for cell integrity. In contrast, plants with a modified nuclear genome expressed much less dsRNA and only slightly slowed down the beetles' growth.

These recent results show that changing the target of transformation from the nuclear genome to the chloroplast genome overcomes the major hurdle towards exploiting RNAi for crop protection. As many insect pests increasingly develop resistances against chemical pesticides and Bt toxins, RNAi represents a promising strategy for pest control. This technology allows for precise protection without chemicals and without production of foreign proteins in the plant.

KD/AO

Contact

Prof. Dr. Ralph Bock
Max Planck Institute of Molecular Plant Physiology
Tel. 0331/567 8211
RBock@mpimp-golm.mpg.de
http://www.mpimp-golm.mpg.de/7889/dep_3

Dr. Kathleen Dahncke
Press and public relations
Max Planck Institute of Molecular Plant Physiology
Tel. 0331/567 8275
dahncke@mpimp-golm.mpg.de
http://www.mpimp-golm.mpg.de

Angela Overmeyer
Press and public relations
Max Planck Institute for Chemical Ecology
Tel. 03641/572 110
overmeyer@ice.mpg.de
http://www.ice.mpg.de

Original publication:
Jiang Zhang, Sher Afzal Khan, Claudia Hasse, Stephanie Ruf, David G. Heckel, Ralph Bock; Full crop protection from an insect pest by expression of long double-stranded RNAs in plastids; Science, February 27th, 2015

Weitere Informationen:

http://www.mpimp-golm.mpg.de - Max Planck Institute of Molecular Plant Physiology
http://www.ice.mpg.de - Max Planck Institute for Chemical Ecology

Ursula Ross-Stitt | Max-Planck-Institut für Molekulare Pflanzenphysiologie

Weitere Nachrichten aus der Kategorie Biowissenschaften Chemie:

nachricht Software mit Grips
20.04.2018 | Max-Planck-Institut für Hirnforschung, Frankfurt am Main

nachricht Einen Schritt näher an die Wirklichkeit
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie

Alle Nachrichten aus der Kategorie: Biowissenschaften Chemie >>>

Die aktuellsten Pressemeldungen zum Suchbegriff Innovation >>>

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

Im Focus: Software mit Grips

Ein computergestütztes Netzwerk zeigt, wie die Ionenkanäle in der Membran von Nervenzellen so verschiedenartige Fähigkeiten wie Kurzzeitgedächtnis und Hirnwellen steuern können

Nervenzellen, die auch dann aktiv sind, wenn der auslösende Reiz verstummt ist, sind die Grundlage für ein Kurzzeitgedächtnis. Durch rhythmisch aktive...

Im Focus: Der komplette Zellatlas und Stammbaum eines unsterblichen Plattwurms

Von einer einzigen Stammzelle zur Vielzahl hochdifferenzierter Körperzellen: Den vollständigen Stammbaum eines ausgewachsenen Organismus haben Wissenschaftlerinnen und Wissenschaftler aus Berlin und München in „Science“ publiziert. Entscheidend war der kombinierte Einsatz von RNA- und computerbasierten Technologien.

Wie werden aus einheitlichen Stammzellen komplexe Körperzellen mit sehr unterschiedlichen Funktionen? Die Differenzierung von Stammzellen in verschiedenste...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Verbesserte Stabilität von Kunststoff-Leuchtdioden

Polymer-Leuchtdioden (PLEDs) sind attraktiv für den Einsatz in großflächigen Displays und Lichtpanelen, aber ihre begrenzte Stabilität verhindert die Kommerzialisierung. Wissenschaftler aus dem Max-Planck-Institut für Polymerforschung (MPIP) in Mainz haben jetzt die Ursachen der Instabilität aufgedeckt.

Bildschirme und Smartphones, die gerollt und hochgeklappt werden können, sind Anwendungen, die in Zukunft durch die Entwicklung von polymerbasierten...

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

VideoLinks
Industrie & Wirtschaft
Veranstaltungen

Internationale Konferenz zur Digitalisierung

19.04.2018 | Veranstaltungen

124. Internistenkongress in Mannheim: Internisten rücken Altersmedizin in den Fokus

19.04.2018 | Veranstaltungen

DFG unterstützt Kongresse und Tagungen - Juni 2018

17.04.2018 | Veranstaltungen

VideoLinks
Wissenschaft & Forschung
Weitere VideoLinks im Überblick >>>
 
Aktuelle Beiträge

Grösster Elektrolaster der Welt nimmt Arbeit auf

20.04.2018 | Interdisziplinäre Forschung

Bilder magnetischer Strukturen auf der Nano-Skala

20.04.2018 | Physik Astronomie

Kieler Forschende entschlüsseln neuen Baustein in der Entwicklung des globalen Klimas

20.04.2018 | Geowissenschaften

Weitere B2B-VideoLinks
IHR
JOB & KARRIERE
SERVICE
im innovations-report
in Kooperation mit academics