How do mutations occur in plants

Mutation breeding

In mutation breeding, mutagenic chemicals such as EMS (ethyl methanesulfonate) randomly insert point mutations into the genome. Since the DNA is changed in an uncontrolled manner, many of the mutants generated in this way are not viable or show undesirable changes. They then have to be disposed of due to defects. Of course, desired mutations also occur, which give the plants new, better properties. Once such a mutation has been identified, it has to be crossed back into a productive breeding line.

 

How do you find the mutations?

If there is a wrong base in the DNA, the complementary strand can no longer attach itself correctly and the DNA forms a hump at this point. Certain enzymes, such as this Cel1, recognize the humps and cut through the DNA at the deformed areas. So there are several small pieces of DNA.

With the help of gel electrophoresis, the length of the DNA pieces can be made visible. If all DNA strands are of the same length, the enzyme has not recognized any deformation and there is no mutation. If DNA strands of different lengths appear, this indicates an activity of the cutting enzyme. A mutation has been encountered. This method is called TILLING.

Mutation breeding is not subject to any legal regulations, as genes are not introduced from other organisms, but the natural mutation frequency is increased. In this way, for example, a potato was bred that no longer produces amylose. The gene for amylose was switched off by an accidental mutation.