Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Simple sugars make cell walls like steel

21.01.2004


Simple sugars apparently are the biological signals needed to maintain the steel-like strength of plant cell walls, according to Purdue University scientists.


Purdue researcher Nick Carpita uses Arabidopsis plants grown in this growth chamber at Purdue’s Hansen Life Sciences Research Building to determine what makes some plant cell walls as strong as steel. (Purdue Agricultural Communications photo/Tom Campbell)



"This is a really fundamental discovery in the mechanics of plant growth that eventually could have several practical applications," said Nick Carpita, a botany and plant pathology professor. "These could include controlling crop plant size and shape, improving desirable textural properties of fruits and vegetables, and enhancing nutritional fibers in plant cell walls without changing other plant structural factors."

Before these goals can be accomplished, however, the scientists must learn as much as possible about how plant cell walls are created and evolve, he said.


Plant cell walls are composites of minute plant fibers interlaced with many different chains of simple sugars, or polymers, that make the structure strong, Carpita said. While studying how cell walls change as plants develop, his research team discovered that an enzyme requires a simple milk sugar, called galactose, to relace polymers during growth.

The scientists report their findings in the January issue of the journal Plant Physiology.

"A plant cell is essentially concentric rings or spools of cellulose, so when the cells expand, the microfibrils of the wall spread apart," Carpita said. "New microfibrils, or minute organic plant fibers, that are synthesized during growth are continually integrated from the inner rings into the outer rings.

"This process prevents the thickness of the wall from changing even as the cell increases 100 or 1,000 times its length."

The galactose needed to ensure wall strength during plant cell growth is attached to some long polymers, he said. However, abnormal plants, or mutants, that are missing the simple sugars lose cell wall tensile strength.

Xyloglucan, a sugar polymer that has several molecules of simple sugars, ties the spools of cellulose together, he said. An enzyme called xyloglucan endo-transglucosylase, or XET, breaks the tether during cell growth to allow the microfibrils to separate. However, XET hangs onto one end of the broken polymer so when a new cellulose fibril forms to fill the space, the enzyme brings old and new xyloglucans together to relace the cellulose to maintain tensile strength. This process not only allows the cell wall to grow, but also is the way growth is finally halted.

"When the plant cells grow, there is a mechanism to loosen the cell walls of the interlacing molecules so the sugar can push those microfibrils apart," Carpita said. "The thickness isn’t compromised because new cellulose microfibrils fill the gap. Unless the xyloglucans are retied or reassociated around the new configurations of microfibrils, the cells will continue to expand indefinitely."

Using the common research plant Arabidopsis, the researchers looked at mutants and found some that developed abnormally. The mutants the scientists studied had an area at the base of the embryonic plant stems, called the hypocotyls, that bulged.

"We isolated the enzyme, isolated the individual polymers, and showed that their activity was severely compromised if the simple sugar galactose was missing from the xyloglucan," Carpita said. "In the plant, the consequence is that the tensile strength of the cell walls is less than half of normal.

"They are really flimsy cells and they bulge out. Instead of being really nice and columnar as this tissue usually is, they get a little flabby. We deduced that these galactose appendages are required for XET to recognize where to clip the xyloglucans to allow expansion and then to retie them."

The scientists want to find out how to control cell wall formation by determining the function of all the genes in their formation, development and growth. This may allow them to improve many everyday products from food to chairs.

The other researchers involved in this study are Maria Peña, currently of Complex Carbohydrate Research Center, University of Georgia; and Peter Ryden and Andrew C. Smith, of the Institute of Food Research, Norwich Research Park, Colney, England; and Michael Madson, Lafayette, Ind.

The U.S. Department of Agriculture National Research Initiative Competitive Grants Program and the Biological Sciences Research Council of Great Britain funded this research.

Writer: Susan A. Steeves, (765) 496-7481, ssteeves@purdue.edu
Source: Nicholas Carpita, (765) 494-4653, carpita@purdue.edu

Susan A. Steeves | Purdue News
Further information:
http://news.uns.purdue.edu/html4ever/2004/040120.Carpita.strength.html
http://cellwall.genomics.purdue.edu
http://www.btny.purdue.edu

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Storage & Transport of highly volatile Gases made safer & cheaper by the use of “Kinetic Trapping"

Augsburg chemists present a new technology for compressing, storing and transporting highly volatile gases in porous frameworks/New prospects for gas-powered vehicles

Storage of highly volatile gases has always been a major technological challenge, not least for use in the automotive sector, for, for example, methane or...

Im Focus: Disrupting crystalline order to restore superfluidity

When we put water in a freezer, water molecules crystallize and form ice. This change from one phase of matter to another is called a phase transition. While this transition, and countless others that occur in nature, typically takes place at the same fixed conditions, such as the freezing point, one can ask how it can be influenced in a controlled way.

We are all familiar with such control of the freezing transition, as it is an essential ingredient in the art of making a sorbet or a slushy. To make a cold...

Im Focus: Micro energy harvesters for the Internet of Things

Fraunhofer IWS Dresden scientists print electronic layers with polymer ink

Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed...

Im Focus: Dynamik einzelner Proteine

Neue Messmethode erlaubt es Forschenden, die Bewegung von Molekülen lange und genau zu verfolgen

Das Zusammenspiel aus Struktur und Dynamik bestimmt die Funktion von Proteinen, den molekularen Werkzeugen der Zelle. Durch Fortschritte in der...

Im Focus: Dynamics of individual proteins

New measurement method allows researchers to precisely follow the movement of individual molecules over long periods of time

The function of proteins – the molecular tools of the cell – is governed by the interplay of their structure and dynamics. Advances in electron microscopy have...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

5th International Conference on Cellular Materials (CellMAT), Scientific Programme online

02.10.2018 | Event News

Major Project: The New Silk Road

01.10.2018 | Event News

"Boston calling": TU Berlin and the Weizenbaum Institute organize a conference in USA

21.09.2018 | Event News

 
Latest News

Physics: Not everything is where it seems to be

15.10.2018 | Physics and Astronomy

Microfluidic molecular exchanger helps control therapeutic cell manufacturing

15.10.2018 | Life Sciences

Link between Gut Flora and Multiple Sclerosis Discovered

15.10.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>