I am interested in carbohydrate metabolism of plants. In particular I wish to understand how car- bohydrate metabolism is coupled to cell wall bio- synthesis, especially to the biosynthesis of cellu- lose. The majority of the biomass accumulation on the planet occurs in the cell walls of non-photo- synthetic plant tissues such as the wood of trees. This biomass resource provides the main source of biopolymers in the world and its importance will increase in the future as global demand for renewable materials and fuels increases.
The work in my group addresses genetic factors contributing to stem biomass and wood density.We focus on the molecular mechanisms responsible for carbon allocation to developing wood of trees.The carbon in wood is mostly found in three main cell wall polymers; cellulose, hemicelluloses and lignin. In most plant species the majority of this carbon is derived from sucrose imported from photosynthetic tissues.Therefore understanding
of sucrose transport to wood and subsequent production of cell wall polymer precursors is central for understanding factors controlling stem biomass and wood density. Our research on carbon allocation to wood is mostly done with hybrid aspen.
|Light microscopy picture of aspen wood fibers and vessels.||Cross section of Arabidopsis stem. Lignified cell walls are shown in red and non-lignified in blue.|
|Cross section of aspen stem.||Developing Arabidopsis seed. Wild type seed and developing embryo (left), and a putative sugar signaling mutant showing defects in embryo development (right).|
In addition to identifying the components of sucrose to cell wall polymer pathways we are interested in how sugar metabolism is regulated in plants, especially in relation to sugar availability.To this end we work on the protein phosphorylation and protein trafficking responses communicating information about the sugar status of plant cells and organs, and how this information is translated to the responses at the cellular and whole plant level. Protein phosphorylation–dephosphorylation and protein trafficking are fundamental principles in the regu- lation of many biological responses in all organisms, including the primary carbohydrate metabolism of plants. In this research we use Arabidopsis seedlings and the developing embryo as model systems.
In our work we use tools from molecular biology, bio- chemistry, genetics, microscopy, isotope flux analysis and mass spectrometry.
- Mahboubi A, Linden P, Hedenström M, Moritz T, Niittylä T (2015). Carbon-13 tracking after 13CO2 supply revealed diurnal patterns of wood formation in aspen. Plant Physiology 168: 478-489.
- Gerber L, Zhang B, Roach M, Rende U, Gorzsás A, Kumar M, Burgert I, Niittylä T and Sundberg B (2014). Deficient sucrose synthase activity in developing wood does not specifically affect cellulose biosynthesis, but causes an overall decrease in cell wall polymers. New Phytologist 203: 1220 – 1230.
- Mahboubi A, Ratke C, Gorzsás A, Kumar M, Mellerowicz EJ, Niittylä T (2013). Aspen SUCROSE TRANSPORTER 3 allocates carbon into wood fibers. Plant Physiology 163, 1729-1740.
- Nystedt et al. (2013). The Norway spruce genome sequence gives insights into conifer genome evolution. Nature, 497, 579-584.
- Roach M, Gerber L, Sandquist D, Gorzsas A, Hedenström M, Kumar M, Steinhauser MC, Feil R, Daniel G, Stitt M, Sundberg B and Niittylä T (2012). Fructokinase is required for carbon partitioning to cellulose in aspen wood. Plant Journal, 70, 967 – 977.