Advances in microscope technology and molecular biology are allowing researchers to see exactly how xylem or wood is formed, in real-time, at the cellular level.
Professor Staffan Persson, a plant cell biologist at the University of Melbourne, said this brings the potential to manipulate the wood formation process and, as a result, develop new materials with a raft of useful properties.
Professor Persson is part of a team of researchers from the University of Melbourne, the University of British Columbia, the Max Planck Institute and Michigan State University. They directly imaged developing xylem cells undergoing the transition from making primary and secondary walls, providing new insights into the process.
The process they imaged centres on the cellulose synthase (CESA) enzyme complexes. These are active at the cell surface, and extrude cellulose out into the cell wall.
Slightly different CESA complexes make primary and secondary wall cellulose. To understand how a plant switches its cellulose production between the two, the researchers needed to identify which CESAs make primary and secondary wall cellulose.
They added fluorescent tags to the CESAs – red tags for primary cellulose factories and green tags for secondary cellulose factories. They then observed the CESAs using a high-end confocal microscope.
Wood typically forms deep within the plant tissue, making it difficult to see with a microscope. Fellow researcher on the project Dr Rene Schneider said they overcame this by forcing other plant cells to produce wood.
“We use a system where we can induce secondary wall cellulose formation in all cells of a plant,” Dr Schneider said.
The system uses a master regulator, or a transcription factor, that switches on genes in the plant that are specific for wood production.
“By using that transcription factor, you can induce wood formation in any plant cell type you want. So now we can make wood at the surface of the plant, which is much easier to image,” he said.
The switch from primary cell wall production to secondary cell wall production is a fast process, taking just a couple of hours. The team watched the red and green-tagged complexes that formed the different cellulose structures and noted the secondary wall cellulose formed faster than primary wall cellulose.
The quality that makes wood valuable as a building material – its durability – can be an impediment to other potential uses but the new research may deliver ways around this.
“Because it is so stable it is hard to get the sugars out of the wood,” Professor Persson said.
“We want to manipulate the process of wood formation to see if we can affect this stability and allow easier extraction of products that can be used for biofuels and materials.”
Source: Phys Org
The full research paper is available online
Photo Credit: CC0 Public Domain
