Scientists Reveal Mechanism of Cell-Wall Composition

Scientists Yu-Chen Miao and Chang-Jun Liu from the U.S. Department of Energy published the results of their investigation on how plant cell walls are formed. They conducted this study with the objective of finding ways to change the cell wall composition of plants for better biofuel production.

Prior to formation of the cell wall, lignin precursors called monolignols are formed in the cell's internal cytoplasm. Some of the monolignols are transported to the internal vacuoles for storage, while some goes out of the cell to be synthesized as lignin. The transport mechanism of these precursors are still unclear. Thus, researchers isolated parts of the cellular and vacuolar membranes from Arabidopsis and poplar plants, and mixed them with monolignols and their derivatives. They monitored the type and the quantity of the precursor that moved across the two membranes in different conditions, including setups with transporter inhibitors.

The assays revealed that pure monolignols pass through the cellular membrane, while monolignol glucosides, a derivative of monolignol, goes into the vacuoles. They also found out that both transport processes do not need adenosine triphosphate or energy. The driving force in the transportation of the precursors was a group of transporters called ATP-binding cassette (ABC).

For more details, read the research article published by the Proceedings of the National Academy of Sciences at http://www.pnas.org/content/early/2010/12/07/1007747108.full.pdf+html?sid=7d3d56a9-ccd8-4276-9eb5-4dbd75b4b8b3.