Less can be more, for plant breeders too( Imagine you are a rice breeder and o...)

Imagine you are a rice breeder and one day within a large field you discover a plant that has just the characteristics you have been looking for. You happily take your special plant to the laboratory where you find out that the spontaneous, beneficial event was due to inactivation of a single gene. This is a great observation; however, there are many different strains grown in different parts of the world, well adapted to the particular region they grow in. How can you now transfer the inactivated gene to other strains of rice? Conventionally, you would have to go through years and years of breeding, until you have successfully transferred that single gene, without affecting all the other genes that are responsible for the target strains being so well adapted to their local environment. Would it not be great, if one could do this faster?

Using inactivated genes for rice breeding might sound far-fetched, but is not unusual. For example, the main change enabling the green revolution in rice resulted from loss of a gene that normally makes rice grow tall (and hence prone to toppling over if a plant makes many heavy rice grains). Thus, transferring inactivated genes is something rice breeders are indeed very much interested in.

Researchers at the Max Planck Institute (MPI) for Developmental Biology in Tbingen, Germany in collaboration with the International Rice Research Institute in the Philippines, have now generated a tool that should greatly speed up this particular aspect of rice breeding: According to a study published in PLoS ONE this week, a team led by Norman Warthmann (MPI) successfully demonstrated highly specific gene silencing using so-called artificial miRNAs in rice (Oryza sativa).

MicroRNAs are 20-22 bp long RNA molecules. In animals as well as in plants they have important functions in regulating gene activity. In plants, they cause highly specific degradation of sequence-matched messenger RNAs, which encode enzymes, regu
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