Employees – University of Copenhagen

Nanna Bjarnholt

Nanna Bjarnholt

Associate Professor

Research area

Plants produce a multitude of complex chemical compounds 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. Elucidation of enzymatic pathways for biosynthesis and catabolism of these compounds is important to understand how they have evolved, what their roles in plants are and ultimately how we may utilize them in e.g. agriculture or medicine.

My particular interest lies in the group of specialized metabolites called cyanogenic glucosides. They serve important roles in plants as deterrents of attack from herbivores and microorganisms. However, they also serve other, less investigated, roles in plants.

For a number of years I have been investigating the physiological roles and catabolism of cyanogenic glucosides, mainly using the crop plant sorghum as a model, but also Lotus japonicus, cassava, barley and almond. My studies of endogenous turnover of cyanogenic glucosides have recently revealed the presence of not one, but several pathways for such catabolism, demonstrating that these compounds play many different roles in plants, including one as nitrogen storage compounds.

This work opened my eyes to the enigma of glutathione transferase enzymes (GSTs). This class of enzymes have been known for several decades, yet remain largely undescribed except for their role in the detoxification pathways of both humans and plants. However, up to 100 different GST enzymes can be found in a single plant and the sheer number indicates that they also serve other, yet unknown, functions. A large part of my research now concentrates on revealing GST functions in specialized metabolism.

My pathway discovery work within non-model plants has caused me to frequently disclose atypical enzymatic functions. I enjoy this exploration of the unknown and at the hearth of my research lies development of tools to ease elucidation of metabolic pathways in non-model plants.

With me, I bring a portfolio of skills that complement each other in opening up this landscape, including Environmental Chemistry, Analytical Chemistry, Plant Biochemistry and Molecular Biology as well as fruitful collaborations, e.g. in Mass Spectrometry Imaging and GSTs (see CV and Collaborations)

Major Collaborations

I have been fortunate to establish fruitful collaborations during my research, including:  
Since 2010: Associate Professor Christian Janfelt, Mass spectrometry imaging, Dept. of Pharmacy, UCPH
Since 2010: Professor Robert Edwards, Glutathione transferases, biology, expression and analyses. School of Agriculture, Food & Rural Development, Newcastle University, UK
Since 2007: Associate Professor Roslyn Gleadow, Sorghum mutant population. Monash University, Melbourne, Australia.



Selected publications

  1. 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
  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. (2016). 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. 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
  4. 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: 
  5. 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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