TILLING: a new tool for plant breeders?

(04 March 2010) An amylose-free potato has been developed by researchers through the use of a new breeding method known as TILLING. Possible use of this method as an alternative to genetic engineering has been postulated in the media.

An acronym for ‘targeting induced local lesions in genomes’, the TILLING procedure uses chemicals and x-rays to cause undirected point mutations in a plant genome. In a second step, DNA analysis is used to select plants with mutations in a desired gene. Mutation effects may include gene deactivation and subsequent back-crossing with other varieties may yield a productive plant with a desirable mutation – for example, an amylose-free potato.

Biotechnology critics including Greenpeace have stated "acceptance" of such methods and cite thereby a "huge difference" to genetic engineering. However, botanists warn of public oversimplification when comparing the methods. First, TILLING is only able to influence existing qualities: new traits such as insect resistance or drought tolerance cannot be generated in plants that are not already genetically coded therefor.

Secondly, the random nature of the first-step mutations means that many plant genes may then not function as they should. Such genes may govern yield, performance and stamina and the conventional breeding processes used to re-obtain these characteristics may necessitate years.

Plants obtained through the TILLING method are not regarded as ‘genetically modified’, are not subject to special regulations and may escape the political context of controversial plants such as the ‘Amflora’ potato. However all breeding methods may lead unexpectedly to negative effects.

Further information:

• GMO Safety: TILLING: The ‘good’ alternative to genetic engineering?