A clever strategy to protect plants against herbivores could be used as an attractive alternative to chemical pest control
RNA Interference (RNAi) is a natural process of gene regulation. According to latest research results it can be used to systematically control insect pests. The potential of this method is described in the latest issue of the journal “Trends in Biotechnology”.
RNAi and its functions
Whether genes are active or not depends on whether genetic information can be read and translated into proteins. The RNA acts as an interpreter between genetic information (DNA) and proteins. If the interpreter is disabled, a translation into proteins is not possible. The mechanism of RNAi does not only make sure that the own genes in an organism can be silenced; this process also helps plants, fungi and insects to protect themselves against viruses. During viral infection, the pathogens introduce their genetic material in the form of double-stranded RNA (dsRNA) into the cell in order to proliferate there. When the viral RNA is replicated in the cell, it is recognized by the RNAi system and fragmented into small pieces. The cell uses these pieces, the so-called siRNAs (small interfering RNAs), to detect and eliminate foreign RNA.
Nature as a model
Scientists from the Max Planck Institute for Chemical Ecology in Jena and the Max Planck Institute of Molecular Plant Physiology in Potsdam-Golm studied this natural mechanism and exploited it for their experiments. In previous studies, they succeeded in using RNAi to protect potato plants against their worst enemy: the Colorado potato beetle. They produced dsRNA, which targets a vital beetle gene, the actin gene, in the cells of potato plants. These plants literally struck the beetles in their stomachs. The insects lost their appetite and stopped growing, because feeding on double-stranded RNA had resulted in the silencing of the actin gene of the beetles: It could no longer be translated into the corresponding protein. The clou of the research project was to prevent that the plant’s own RNAi system eliminates the introduced dsRNA immediately and thus renders it ineffective against the beetle. Since the chloroplasts of plant cells do not possess an RNAi system, the scientists used chloroplasts for dsRNA production rather than cell nuclei.