Ansatte på Institut for Plante- og Miljøvidenskab – Institut for Plante- og Miljøvidenskab - Københavns Universitet

Nanna Bjarnholt

Nanna Bjarnholt

Lektor

Research area

Plants produce a multitude of complex metabolites to navigate their interaction with the environment, e.g. as defense compounds. Some of these compounds are used by humans for medicine, food supplements, color pigments etc, while others are important determinants of crop plants’ nutritional value for humans and fodder crops for animals. For a number of years I have been investigating the physiological roles and catabolism of cyanogenic glycosides, mainly using the crop plant sorghum as a model, but also Lotus japonicus, cassava, barley and almond. Cyanogenic glycosides serve important roles in plants as deterrents of attack from herbivores and microorganisms. However, they also serve other, less investigated, roles in plants, and most of my research has focused on elucidating these functions and the associated enzymatic pathways. This work has caused me to frequently discover atypical enzymatic functions, one of them a reductive cleavage reaction carried out by glutathione transferase enzymes (GSTs) in a pathway for recovery of nitrogen from cyanogenic glucosides. The enzyme family of GSTs is large and complex and with very few identified physiological functions. With a young investigator grant from the VILLUM Foundation my group will now focus on revealing other functions of GSTs in specialized metabolism.

Projects

  • GSTspecial: Glutathione transferases in plant specialized metabolism. Identification of GST functions to shed light onto mysterious enzyme family and identify new tools for future pathway discovery.
  • Physiological functions of cyanogenic glucosides and related compounds, in crop plants and model plants.
  • Advancing mass spectrometry imaging for plant tissues

Web

  • https://plantplasticity.ku.dk/research/metabolic/
  • https://plen.ku.dk/english/research/plant_biochemistry/cgvsc/

Key technologies

  • Mass spectrometry imaging
  • Metabolomics; state-of-the-art LC-MS and GC-MS
  • Transcriptomics
  • Molecular cloning,  heterologous expression, in vitro enzyme assays
  • Mutant plant characterization

Major Collaborations

Associate Professor Christian Janfelt - Mass spectrometry imaging - Dept. of Pharmacy, University of Copenhagen
Professor Robert Edwards - Glutathione transferases, biology, expression and analyses - School of Agriculture, Food & Rural Development, Newcastle University, UK

Professor Ian Godwin – Sorghum transformation, CRISPR-CAS, mutant population – University of Queensland, Brisbane, Australia
Professor Roslyn Gleadow - Sorghum mutant population - Monash University, Melbourne, Australia.

Current funding

VILLUM Young Investigator grant, The VILLUM Foundation, Denmark, grant number 19151

Co-PI of VILLUM Research Center for Plant Plasticity (www.plantplasticity.ku.dk), The VILLUM Foundation, Denmark, grant number VKR023054

 

Selected publications

  1. Bjarnholt, N., Neilson, E.H., Crocoll, C., Nielsen, L.J., Jørgensen, K., Motawia, M.S., Olsen, C.E., Dixon, D.P., Edwards, R., Møller, B.L. (accepted March 2018). Nitrogen recycling from cyanogenic glucosides in Sorghum bicolor is mediated by glutathione transferases. Plant J. In press.
  2. Mnich, E., Vanholme, R., Oyarce, P., Liu, S., Lu, F., Goeminne, G., Jørgensen, B., Motawie, M.S., Boerjan, W., Ralph, J., Ulvskov, P., Møller, B.L., Bjarnholt, N., Harholt, J. (2017). Degradation of lignin β-aryl ether units in Arabidopsis thaliana expressing LigD, LigF and LigG from Sphingomonas paucimobilis SYK-6. Plant Biotech. J. doi: 10.1111/pbi.12655
  3. Nielsen, L. J., Stuart, P., Pičmanová, M., Rasmussen, S., Olsen, C. E., Harholt, J., Møller, B. L. & Bjarnholt, N. (2016). Dhurrin metabolism in the developing grain of Sorghum bicolor (L.) Moench investigated by metabolite profiling and novel clustering analyses of time-resolved transcriptomic data. BMC Genomics 17 (1): 1021 DOI: 10.1186/s12864-016-3360-4
  4. Pičmanová, M. , Neilson, E.H., Motawia, M.S., Olsen, C.E. , Agerbirk, N., Gray, C.J., Flitsch, S., Meier, S., Silvestro, D., Jørgensen, K., Sánchez-Pérez, R., Møller, B.L., Bjarnholt, N. (2015). A recycling pathway for cyanogenic glycosides evidenced by the comparative metabolic profiling in three cyanogenic plant species. Biochem. J. 469 (3): 375-389 doi: 10.1042/BJ20150390
  5. Bjarnholt, N., Li, B., D'Alvise, J., Janfelt, C. (2014). Mass spectrometry imaging of plant metabolites - principles and possibilities. Nat. Prod. Rep. 31 (6):818-837 doi: 
    10.1039/C3NP70100J
  6. Li, B., Knudsen, C., Hansen, N.K., Jørgensen, K., Kannangara, R., Bak, S., Takos, A., Rook, F., Hansen, S.H., Møller, B.L., Janfelt, C., Bjarnholt, N. (2013). Visualizing metabolite distribution and enzymatic conversion in plant tissues by desorption electrospray ionization mass spectrometry imaging. Plant J. 74 (6): 1059-1071. doi: 10.1111/tpj.12183

 

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