Navigation Links
Scientists unravel more details of plant cell-wall construction
Date:12/13/2010

UPTON, NY - One big challenge in converting plants to biofuels is that the very same molecules that keep plants standing up make it hard to break them down. Now scientists at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory are unraveling details of how plant cells' structural supports - their cell walls - are made, with the hope of finding ways to change their composition for more efficient biofuel production.

In a paper to be published the week of December 13, 2010, in the Proceedings of the National Academy of Sciences, the researchers describe details of how precursors to lignin, one important cell-wall component, are transported across cellular membranes prior to linking up. The key finding, that the process requires a class of energy-dependent transporter molecules, may provide a "chink in the armor" that opens a way to alter plants' lignin content.

"Being able to manipulate lignin biosynthesis would have a great influence on our ability to produce renewable biofuels from plant cellulosic feedstocks, and could also have a large effect on many other agricultural and industrial processes, such as the production of paper and more digestible foods for grazing animals," said lead author Chang-Jun Liu, a Brookhaven biologist.

Prior to cell-wall construction, lignin precursors known as monolignols are made in the cell's interior cytoplasm. Some precursors may be sequestered in internal vacuoles for storage, while some move out of the cell to link up and form the lignin component of the cell wall - a protective and supportive barrier around the cell. In both cases, the precursors move across a membrane, either out of the cell or into the vacuole. But no one was certain how the process occurred - whether by simple diffusion or via some active transport mechanism.

The Brookhaven team unraveled the mystery by isolating portions of cellular and vacuolar membrane from Arabidopsis and poplar plants, making them into closed vesicles that resemble bubbles, and mixing in pure monolignols and ones that have been chemically modified to form monolignol glucosides, which are commonly observed in some plants. They then monitored which type and how much of each precursor moved across the two kinds of membranes and into the vesicles under a range of conditions, including in the presence of inhibitors for different kinds of transport molecules.

The range of assays revealed that pure monolignols move across the cellular membrane while monolignol glucosides move preferentially into vacuoles. But most importantly, very little of either precursor would move across either type of membrane without the addition of ATP, the molecular "currency" for energy in cells.

"ATP is the energy molecule that is well known for providing the driving force for a group of transporters called ATP-binding cassette (ABC) transporters on cell membranes," Liu said.

To prove the point, adding an agent that specifically inhibits ABC transporters completely blocked uptake of lignin precursors by both types of membrane vesicles.

With these experiments and additional evidence, Liu and his colleagues demonstrated that ABC-like transporters on cell membranes are responsible for the transport of lignin precursors.

Now that the scientists have identified a class of transporters likely involved in sequestering and transporting lignin's building blocks, they'll pursue detailed studies to identify exactly which members of the class are involved.

"If we can identify those particular transporters we might be able to control their expression to reduce the precursor deposited into the cell wall, and thus lower the cell-wall content of lignin -or, selectively control the particular type of precursor deposited to change lignin composition and produce more easily cleavable biopolymers," Liu said.


'/>"/>

Contact: Karen McNulty Walsh
kmcnulty@bnl.gov
631-344-8350
DOE/Brookhaven National Laboratory
Source:Eurekalert

Related biology news :

1. Jefferson scientists deliver toxic genes to effectively kill pancreatic cancer cells
2. Scientists identify novel inhibitor of human microRNA
3. Argonne scientists peer into heart of compound that may detect chemical, biological weapons
4. MU scientists go green with gold, distribute environmentally friendly nanoparticles
5. Scientists identify gene that may contribute to improved rice yield
6. Scientists discover why a mothers high-fat diet contributes to obesity in her children
7. MU scientists see how HIV matures into an infection
8. Earth scientists keep an eye on Texas
9. Thinking it through: Scientists call for policy to guide biofuels industry toward sustainability
10. Scientists identify a molecule that coordinates the movement of cells
11. Scientists Find new migratory patterns for Mediterranean and Western Atlantic bluefin tuna
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/2/2016)... Feb. 2, 2016  Based on its recent ... Sullivan recognizes US-based Intelligent Retinal Imaging Systems (IRIS) ... Award for New Product Innovation. IRIS, a prominent ... North America , is poised to set ... diabetic retinopathy market. The IRIS technology presents superior ...
(Date:1/28/2016)... Calif., Jan. 28, 2016 Synaptics (NASDAQ: SYNA ), ... for its second quarter ended December 31, 2015. ... quarter of fiscal 2016 increased 2 percent compared to the comparable ... quarter of fiscal 2016 was $35.0 million, or $0.93 per diluted ... net income for the first quarter of fiscal 2016 grew 9 ...
(Date:1/22/2016)... 22, 2016 ... of the  "Global Behavioral Biometric Market ... --> http://www.researchandmarkets.com/research/4lmf2s/global_behavioral ) has announced ... Biometric Market 2016-2020"  report to their ... Markets ( http://www.researchandmarkets.com/research/4lmf2s/global_behavioral ) has announced the ...
Breaking Biology News(10 mins):
(Date:2/4/2016)... ... February 04, 2016 , ... Morf ... today announced an interactive FDA compliance training course, Writing Effective ... Professional Society) accredited interactive course on Morf Playbook—now conveniently available on smartphones and ...
(Date:2/4/2016)... ... February 04, 2016 , ... ... and triple quad LC-MS, host live demos and poster sessions, and present on ... exhibition. The conference takes place March 6 to 10 at the Georgia World ...
(Date:2/4/2016)... MONMOUTH JUNCTION, N.J. , Feb. 4, 2016 ... critical care immunotherapy leader commercializing its flagship CytoSorb® ... and cardiac surgery patients around the world, announced ... PhD, will present at the Source Capital Group,s ... overview and update on the company.  ...
(Date:2/4/2016)... 4, 2016 ContraVir Pharmaceuticals, Inc. (NASDAQ: ... and commercialization of targeted antiviral therapies, announced today that ... 2016, to be held February 8-9, 2016, at the ... Disruptive Growth & Healthcare Conference, taking place in ... James Sapirstein , Chief Executive Officer of ...
Breaking Biology Technology: