My main interest is in carbohydrate metabolism and cell wall biosynthesis. In particular I wish to understand how carbohydrate metabolism is coupled to cell wall biosynthesis, especially to the biosynthesis of cellulose. The majority of the biomass accumulation on the planet occurs in the cell walls of non-photosynthetic plant tissues such as the wood of trees. This biomass resource provides the main source of biopolymers in the world, and its importance as renewable resource is likely to increase in the future.

Totte Niittyla 1150

Most of 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.
Transcriptional regulation clearly plays an important role in these processes, and we are applying different genomics tools to identify transcription factors involved in stem biomass accumulation. We are also working at the interface of wood biology and material science with the aim of using natural variation and modern tree breeding tools to improve the suitability of wood for nanocellulose production. Our plant cell wall and wood research is done with Arabidopsis, aspen and Norway spruce.

totte_1 Arabidopsis stem 880
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.
Aspen stem 880 Picture4
 Cross section of aspen stem. Siliques of wild type Arabidopsis and opnr-1 showing the seed abortion phenotype (left). Elongated zygotes of wild type and opnr-1 (middle). Confocal microscopy images showing the dual localisation of OPNR in nuclear envelope and mitochondria labelled with PHB3-mCherry (right).

In addition to wood biology, I have an interest in fundamental cellular processes. Aspen is an excellent model system for many questions in tree biology, but less well suited for investigating plant cell biology. In this context, it is striking that one third of the genes in the most explored model plant Arabidopsis remain of unknown function. We are interested in identifying essential genes, which are indispensable for the function of a plant cell and constitute the minimum gene set required for cellular life. Our ambition is to push new inroads to this unknown territory of plant cell biology. Our approach is to investigate evolutionarily-conserved single copy Arabidopsis genes of unknown function with predominant expression in meristematic cells.
Evolutionarily-conserved single copy genes in flowering plants have been shown to be enriched in essential housekeeping functions. In this project, we recently identified an essential gene we named OPENER (OPNR). opnr mutants show zygotic lethality and endosperm arrest. Intriguingly, OPNR localizes to both nuclear envelope and mitochondria. Connections between subcellular compartments and proteins with dual function is an emerging research frontier in plant cell biology, and OPNR opens a line of investigation into a previously uncharacterized essential process occurring in both nucleus and mitochondria in dividing plant cells.

In our work, we use state-of-the-art tools from molecular biology, biochemistry, genomics, genetics, microscopy, isotope analysis, mass spectrometry and automated plant growth phenotyping.

sweden_greySvensk sammanfattning

Publication list

  1. Two-step derivatization for determination of sugar phosphates in plants by combined reversed phase chromatography/tandem mass spectrometry
    Plant Methods 2019, 15(127)
  2. Isolation and characterization of cellulose nanofibers from aspen wood using derivatizing and non-derivatizing pretreatments
    Cellulose 2019, First Online October 3
  3. Genome-Wide Association Study (GWAS) identified novel candidate loci affecting wood formation in Norway spruce
    Plant J. 2019, July Early access
  4. OPENER Is a Nuclear Envelope and Mitochondria Localized Protein Required for Cell Cycle Progression in Arabidopsis
    Plant Cell 2019, 31(7):1446-1465
  5. High Spatial Resolution Profiling in Tree Species
    Annual Plant Reviews Online 2019
  6. Cellulose synthase stoichiometry in aspen differs from Arabidopsis and Norway spruce
    Plant Physiology 2018, 177 (3):1096-1107
  7. Sucrose transport and carbon fluxes during wood formation
    Physiologia Plantarum 2018, 164(1):67-81
  8. Two Complementary Mechanisms Underpin Cell Wall Patterning during Xylem Vessel Development
    Plant Cell. 2017, 29 (10):2433-2449
  9. AspWood: High-spatial-resolution transcriptome profiles reveal uncharacterized modularity of wood formation in Populus tremula
    Plant Cell. 2017, 29 (7):1585-1604
  10. Spatially resolved metabolic analysis reveals a central role for transcriptional control in carbon allocation to wood
    J Exp Bot 2017, 68 (13):3529-3539
  11. Laser Capture Microdissection Protocol for Xylem Tissues of Woody Plants
    Front. Plant Sci., 04 January 2017
  12. Cytosolic invertase contributes to the supply of substrate for cellulose biosynthesis in developing wood
    New Phytol. 2017, 214(2):796-807
  13. Carbon-13 tracking after 13CO2 supply revealed diurnal patterns of wood formation in aspen
    Plant Physiol. 2015; 168(2):478-489
  14. Deficient sucrose synthase activity in developing wood does not specifically affect cellulose biosynthesis, but causes an overall decrease in cell wall polymers
    New Phytol. 2014, 203(4):1220-1230
  15. Aspen SUCROSE TRANSPORTER 3 allocates carbon into wood fibers
    Plant Physiology 2013; 163(4):1729-1740
  16. The Norway spruce genome sequence and conifer genome evolution
    Nature 2013; 497(7451):579-584
  17. Xue W, Ruprecht C, Street N, Hematy K, Chang C, Frommer WB, Persson S, Niittylä T
    Paramutation-Like Interaction of T-DNA Loci in Arabidopsis
    PLoS ONE 2012 7(12): e51651
  18. Roach M, Gerber L, Sandquist D, Gorzsás A, Hedenström M, Kumar M, Steinhauser MC, Feil R, Daniel G, Stitt M, Sundberg B, Niittylä T
    Fructokinase is required for carbon partitioning to cellulose in aspen wood
    Plant Journal, 2012, 70(6):967 – 977
  19. Niittylä T, Chauduri B, Sauer U and Frommer WB
    Comparison of quantitative metabolite imaging tools and carbon-13 techniques for fluxomics
    Methods Mol Biol, 2009, 553:355-372
  20. Niittylä T, Fuglsang AT, Palmgren MG, Frommer WB, Schulze WX
    Temporal analysis of sucrose-induced phosphorylation changes in plasma membrane proteins of Arabidopsis
    Mol Cell Proteomics, 2007,6:1711-1726
  21. Chaudhuri B, Niittylä T, Hörmann F, Frommer WB
    Fluxomics with ratiometric metabolite dyes
    Plant Signal Behav. 2007, 2(2):120-2
  22. Niittylä T, Comparot-Moss S, Lue W-L, Messerli G, Trevisan M, Seymour MD, Gatehouse JA, Villadsen D, Smith SM, Chen J, Zeeman SC, Smith AM
    Similar protein phosphatases control starch metabolism in plants and glycogen metabolism in mammals
    J. Biol. Chem. 2006, 281:11815-11818
  23. Niittylä T, Messerli G, Trevisan M, Chen J, Smith AM, Zeeman SC
    A previously unknown maltose transporter essential for starch degradation in leaves
    Science 2004, 303:87-89
  24. Smith AM, Zeeman SC, Niittylä T, Kofler H, Thorneycroft D, Smith SM
    Starch degradation in leaves
    J. Appl. Glycosci. 2003, 50:173-176
  25. Zabela MD, Fernandez-Delmond I, Niittylä T, Sanchez P, Grant M
    Differential expression of genes encoding Arabidopsis phospholipases after challenge with virulent or avirulent Pseudomonas isolates
    Mol. Plant Microbe Interact. 2002, 15:808-816