Fraunhofer: Precision breeding creates super potato

Research lead

Researchers at the Fraunhofer Institute for Molecular Biology and Applied Ecology (IME) have developed a way to speed up plant breeding without using any form of genetic modification.

Tilling, or Targeting Induced Local Lesions in Genomes, is claimed as a way of speeding up the natural process of evolution. “We are working here with natural principles. In nature, sunlight triggers changes in the genome,” says Jost Muth of IME. “With the aid of chemicals, a vast number of mutants can be rapidly obtained. With chemistry, we accomplish the same thing – only faster.”

Until now, mutation breeding was an exhaustive process. Growers had to plant the mutated seeds to the field, and then wait until they reached the end of their vegetation period in order to determine if one of the genetic modifications achieved the desired result. In addition, the effect of the majority mutations could not be determined, since the characteristic is only expressed in a homozygous state.

In the speeded-up process mutated seeds were germinated and as soon as the first leaves appear, they are harvested. The researchers take a leaf sample, break apart the cellular structure, isolate the genome and analyse it. In this way they can find out within a few weeks if a mutation has attained the desired traits.

The technique has been applied to develop a new breed of Tilling potato, which exclusively contains amylopectin starch. This autumn the German potato starch manufacturer the Emsland Group processed the first crop. Not only can nutritional starches for emulsifying soups and desserts be extracted from it – it can also be used for paste and coatings for paper and thread production.

In a project sponsored by the Nachwachsende Rohstoffe agency, researchers at IME, in collaboration with the Bioplant and Emslandstärke companies, found the super potato germ. They had to examine the genome of 2,748 seedlings until just the right one was identified that exclusively produces amylopectin. From this germ, the first generation of super potatoes was produced. These have active genes that produce amylopectin, whereas genes that trigger the formation of amylose are shut-off. Until now, potatoes always contained both starch types and industrial processors had to separate the amylopectin from the amylase, an energy and cost-intensive process.

This autumn, 100 tonnes of the Tilling potato, which exclusively produces amylopectin, were harvested. They can be processed as usual in the regular production lines. The special measures that would be required if they were genetically modified, to separate them from other potatoes, are not required.

“Special measures aren't necessary, because the Tilling potatoes are totally normal breeds that contain no genetically modified material,” said Muth. The example shows that conventional or modern breeding methods can be speeded up if the gene responsible for the expression of a specific trait is a natural part of the plant.