Making “Better” Plant Cell Walls
The lignocellulosic materials that comprise the secondary cell walls of plants provide sugars for fermentation to second generation biofuels. This rigid material provides structural support for plant and a means by which they resist pathogens and other stresses, but this same strength makes it difficult and expensive to degrade into sugars for the fermentation and production of biofuels. Researchers at the DOE Bioenergy Sciences Center (BESC) have identified a gene in the model legume Medicago truncatula (barrel medic) that is involved in secondary cell wall thickening. Plants containing a mutant form of this gene exhibited reduced lignin content, altered cell walls, and unopened anthers. When subjected to chemical and enzyme treatments, these mutants released significantly more sugars for fermentation than the wild type. Additionally, since pollen is not released from the anthers, seed development in this self-pollinating plant is prevented, providing a natural means of preventing the unwanted spread of this plant in nature. These desirable features suggest that this gene would be a good target for genetic engineering for plant feedstock improvement. The research was carried out at Oak Ridge National Laboratory, lead institution for BESC, and with their partners at the Samuel Roberts Noble Foundation and the National Renewable Energy Laboratory (NREL).
Zhao Q, Gallego-Giraldo L, Wang H, Zeng Y, Ding S-H, Chen F, and Dixon RA. 2010. “An NAC transcription factor orchestrates multiple features of cell wall development in Medicago truncatula.” Plant Journal 63(1):100-114.