| Summary: | The secondary cell wall is vitally important to the physiology of vascular plants. The evolution of specialised water conducting cells supported by secondary cell wall material, together with the mechanical strength afforded by secondary cell walls, has allowed vascular plants to diversify enormously in their structure, and to become one of the most varied and successful forms of life on earth. Cell wall-based materials can also be used as a source of energy - either directly, or as a feedstock for advanced liquid biofuels. The structure and composition of the secondary cell wall, however, makes it difficult to liberate the free sugars required for biofuel production, and the starting biomass often requires pre-processing. Modification of the secondary cell wall could potentially reduce the amount of biomass pre-processing required, and thus increase the overall efficiency of the biofuel production process (Himmei et at., 2007). In order to make such targeted modifications of cell wall traits, we must first understand the genetic network that regulates secondary cell wall development. MYB26, a master regulator of secondary cell wall formation in the endothecium cell layer of Arabidopsis (Steiner-Lange et at., 2003; Yang et ah, 2007), provides a starting point to analyse the genetic network underlying secondary cell wall development. A number of complementary experimental approaches were used in this study to extend the transcriptional network of secondary cell wall development regulated by MYB26, including: global transcriptional profiling, comparative transcriptomics, qPCR time-course experiments, and analysis of T-DNA insertion lines. Other experimental techniques, such as yeast one-hybrid screens and chromatin immunoprecipitation, were used to add structure to the general network by examining direct regulatory relationships - and an oligonucleotide pull-down experiment using recombinant MYB26-GST protein was used to identify a possible consensus binding sequence for MYB26.
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