Breeding potatoes with improved properties

Nov 29, 2010
By equipping potatoes with genes involved in starch synthesis in other organisms, potatoes get the ability to produce new types of starch granules. Centre: regular starch granule of potato, around it: new types of granules.

It is possible to breed potatoes in such a way that they produce new types of starch for use as a new and improved plant-based raw material in the construction, paper, glue, fodder and food industries. These results are described in Xingfeng Huang’s PhD thesis, which he will defend on 29 November 2010 to obtain his doctoral degree at Wageningen University.

Using genetic modification, Huang managed to develop with larger starch granules, a higher capacity to retain water after several cycles of freeze/thaw (interesting, fro example, with frozen meals) and have a stronger capacity to form gels (useful when making sauces).

The cells of tubers contain starch in the form of starch granules. The plant produces these granules because enzymes adhere to the outside of the granule, building up the starch granule. The enzymes adhere to the granules because a specific part of the enzyme, the so-called Starch Binding Domain, is able to recognise starch.

Enzyme cooperation

The way the granule is built up depends on the activity of the rest of the enzyme. The cooperation between the enzymes involved in starch biosynthesis affects the shape and size of the starch granules, as well as other starch properties such as the ability to ‘bind’ water, as required when making sauces and soups.

There are bacteria that contain enzymes involved in the breakdown of starch and these enzymes also have a Starch Binding Domain. They often have a slightly different function than the enzymes already present in the potato. If potatoes were able to produce these enzymes, it would probably result in starch granules with new characteristics. This could make the potato an even better source for plant-based raw materials; materials that are sustainably produced in plants.

New starch via new enzymes

Via genetic modification, Huang introduced genes in the potato which code for proteins that combine a Starch Binding Domain with different bacterial enzymes involved in starch modification. Huang discovered that the new ‘fusion enzymes’ often caused the potato plants to produce starch granules with an entirely different appearance than the granules usually found in potato cells.

When Huang used the gene for the amylosucrase of the Neisseria polysaccharea bacteria, it also changed other important characteristics of the starch granules. The granules were on average twice as large, for instance, and the starch was more capable of ‘binding’ fluids. This means that smaller amounts of starch can produce the same viscosity in, for example, sauces and desserts.

It was also shown that the new starch granules were better at retaining water, which is highly relevant to frozen food products. When the starch in these products discharges too much water, they can often no longer be used once they have been defrosted.

Huang’s research shows that it is indeed possible to develop potatoes that produce new, better sustainable raw materials. Potato starch is already being used in the construction paper, , fodder and food industries. New types of starch could benefit these and other possible applications.

Explore further: Chickens to chili peppers: Scientists search for the first genetic engineers

add to favorites email to friend print save as pdf

Related Stories

Spuds that like you -- in your summer salad

Jun 25, 2007

It has long been known that eating potatoes is good for bowel health, but new research suggests that they may also have a beneficial effect on the whole immune system. Especially if eaten cold or in a potato salad, Anne Pichon ...

SEX4, starch and phosphorylation

Jun 26, 2008

Some of the new molecular mechanisms and regulatory components in starch metabolism have been identified by Dr. Samuel Zeeman and his colleagues. Dr. Zeeman, of the Institute of Plant Sciences, ETH Zurich, in Switzerland, ...

Corn's roots dig deeper into South America

Mar 24, 2008

Corn has long been known as the primary food crop in prehistoric North and Central America. Now it appears it may have been an important part of the South American diet for much longer than previously thought, according to ...

Enzyme in saliva shapes how we sense food texture

Oct 13, 2010

Creamy. Gritty. Crunchy. Slimy. Oral texture perception is a major factor contributing to each person's food preferences. Now, a new study from the Monell Center reports that individuals' perception of starch texture is shaped ...

Natural plant materials to regulate starch digestion

Jun 16, 2008

Researchers in Switzerland are reporting discovery of natural plant materials that may regulate starch digestion — slowing down the body's conversion of potatoes, rice, and other carbohydrate-rich foods into sugar. The ...

Discovery advances control of starch digestion

Jun 04, 2010

(PhysOrg.com) -- Controlling diet-induced degenerative disorders such as Type II Diabetes and obesity could be as easy as sprinkling a dietary supplement on your food in the future.

Recommended for you

Deadly human pathogen Cryptococcus fully sequenced

18 hours ago

Within each strand of DNA lies the blueprint for building an organism, along with the keys to its evolution and survival. These genetic instructions can give valuable insight into why pathogens like Cryptococcus ne ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Scientists tether lionfish to Cayman reefs

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Continents may be a key feature of Super-Earths

Huge Earth-like planets that have both continents and oceans may be better at harboring extraterrestrial life than those that are water-only worlds. A new study gives hope for the possibility that many super-Earth ...

Under some LED bulbs whites aren't 'whiter than white'

For years, companies have been adding whiteners to laundry detergent, paints, plastics, paper and fabrics to make whites look "whiter than white," but now, with a switch away from incandescent and fluorescent lighting, different ...