Secondary walls are the major constituent of tracheary elements and fibers (types of plant cells) in wood, and constitute most abundant biomass produced by plants. Understanding the molecular mechanisms that regulate the switching on and off the genes (a process called transcription) needed for secondary wall biosynthesis during wood formation is a critical issue in plant biology and will have important implications in biofuel production. It was recently discovered that the secondary wall-associated NAC domain of the transcription factor SND1 (a protein that regulates transcription) is a master switch activating the developmental program of secondary wall biosynthesis. The current hypothesis is that SND1 together with its downstream transcription factors exert combinatorial transcriptional regulation of secondary wall biosynthetic genes. The aim of this project is to unravel this combinatorial transcriptional regulatory program by identification of direct targets of SND1 downstream transcription factors and investigation of the developmental switches controlling SND1 expression. The project outcomes will provide a comprehensive picture of how the concerted actions of multilayered transcriptional switches result in the activation of the secondary wall biosynthetic program. The proposed work will contribute to the understanding of the molecular mechanisms underlying wood formation, which will potentially provide valuable tools for genetically improving the quality and quantity of wood, the most important raw materials for traditional forest products and potentially for biofuel production. The project will also involve the training of graduate and undergraduate students and its outcomes will be disseminated in a timely fashion to enhance the understanding of plant biology research and its benefits to society.
