¡@¡@Wood is the most important raw material for the production of pulp for paper making, of lumber for construction and furniture, and of ethanol for energy. Wood formation is a complex developmental process involving differentiation of secondary xylem cells from the vascular cambium, followed by thickening of the cell wall (secondary cell wall). Growth and development in multicellular organisms are regulated at many levels by transacting molecules following well-structured regulatory hierarchies. Understanding the regulatory hierarchy of wood formation will offer novel and more precise genetic approaches to improve the productivity of forest trees. Using Populus trichocarpa protoplasts from stem-differentiating xylem (SDX) as a model, we have begun to reveal the transcriptional regulatory network involved in secondary cell wall formation.
¡@¡@Wood is secondary xylem and, in angiosperm trees, consists of three types of cells, fiber, vessel and ray. In vascular cambium, a thin layer of undifferentiated cells, the fusiform initials or the stem cells, divides and differentiates to give rise to all the three wood cell types. The three types of cells have unique functions. Fiber cells provide support, vessels transport water, and ray cells store nutrients and extractives. Of the three cell types, fibers and vessel elements are the two major ones, with fibers accounting for approximately 60 to 80% of the wood volume. We will use Laser Capture Microdissection (LCM) to isolate vascular cambium, fiber, vessel, and ray cells to study the mechanism of xylem development.
¡@¡@Biofuels and biomass depend on plants as feedstocks for fermentation and other energy related processing. Wood, the most abundant form of plant biomass, can be produced sustainably on land that is not suitable for food crops. Understanding wood formation would improve plant productivity, production of materials, energy, and food. A sustainable and abundant wood supply continues to be an essential national resource.
Wang P.J.*, Chuang L.*, Loziukc P.L., Chen H., Lin Y.C., Shi R., Qu G.Z., Muddiman D.C., Sederoff R.R., Chiang V.L. (2015). Phosphorylation is an on/off switch for 5-hydroxyconiferaldehyde O-methyltransferase activity in poplar monolignol biosynthesis. Proceedings of the National Academy of Sciences USA. 112, 8481¡V8486. (* Co-first author).
Lin Y.C., Li, W., Li, Q.Z., Chen, H., Sederoff, R.R., and Chiang, V.L. (2014). A simple improved-throughput xylem protoplast system for studying wood formation. Nature Protocols. 9, 2194-2205.
Li, W., Lin Y.C., Li, Q.Z., Chen, H., Sederoff, R.R., and Chiang, V.L. (2014). A robust chromatin immunoprecipitation protocol for studying transcription factor¡VDNA interactions and histone modifications in wood-forming tissue. Nature Protocols. 9, 2180-2193.
Chen, H.-C.*, Song, J.*, Wang, P.J.*, Lin Y.C., Ducoste, J., Shuford, M.C., Liu, J., Li Q., Shi, R., Nepomuceno, A., Isil, F., Muddiman, C.D., Williams, C., Sederoff, R.R., and Chiang L.C. (2014). Systems Biology of Lignin Biosynthesis in Populus trichocarpa: Heteromeric 4-Coumaric acid: CoA Ligase (4CL) Protein Complex Formation, Regulation and Numerical Modeling. Plant Cell. 26, 876-893. (* Co-first author).
Lin Y.C.*, Li, W.*, Sun, Y.H., Kumari, S., Wei, H.R., Li, Q.Z., Tunlaya-Anukit, S., Sederoff, R.R., and Chiang, V.L. (2013). SND1 transcription factor-directed quantitative functional hierarchical genetic regulatory network in wood formation in Populus trichocarpa. Plant Cell. 25, 4324-4341. (* Co-first author).
Li Q.*, Lin Y.C.*, Sun Y. H., Song J., Chen H., Zhang X. H., Sederoff R. R., and Chiang V. L. (2012). Splice variant of the SND1 transcription factor is a dominant negative of SND1 members and their regulation in Populus trichocarpa. Proceedings of the National Academy of Sciences USA. 109, 14699-14704. (* Co-first author).
Wang J.P., Shuford C.M., Li Q., Song J., Lin Y.C., Sun Y.H., Chen H.C., Williams C.M., Muddiman D.C., Sederoff R.R., Chiang V.L. (2012). Functional redundancy of the two 5-hydroxylases in monolignol biosynthesis of Populus trichocarpa: LC-MS/MS based protein quantification and metabolic flux analysis. Planta. 236, 795-808.