Nutrient transport, compartmentation and speciation


In the research theme “Nutrient transport, compartmentation and speciation” we investigate how mineral ions are transported, assimilated and stored in various plant tissues. The main objectives are to understand how plants cope with nutrient deficiency/toxicity, and to evaluate nutrient use efficiency; i.e. how efficient different plants and plant varieties are at foraging the nutrients available in the soil. We also evaluate biofortification, which is a set of strategies aiming to improve the nutritional value of the edible plant parts, e.g. cereal grains.

Any nutrient ion needed by the plants needs to pass through the different root tissues and reach the xylem vessels in order to be transported to the shoot. However, nutrient and other ions in the soil solution are not present in ideal concentrations; hence the plant must regulate the type and amounts of ions taken up and transported. Plant roots have a number of ways in which it can control and regulate this transport, which is reflected in root barrier formation (Casparian strip and suberin deposition), exudation and regulation of transporters. We utilize laser ablation based bioimaging tools to study the tissue compartmentation of mineral ions. This allows us to study how ions are distributed in grain tissue and how nutrient interactions influence the cellular distribution.

Furthermore, most nutrients never travel alone through the plant and usually they are bound to various molecular species such as organic acids, amino acids or small peptides. Likewise, when nutrients are deposited in seeds, grains and fruits of plants they also interact with species such as proteins and various carbohydrates. We use a range of sophisticated technologies to study this molecular speciation of nutrients, including various combinations of chromatography with ICP-MS (LC-ICP-MS). In our research projects we study how minerals are loaded and distributed in the cereal grain and how the speciation of micronutrients change during digestion, which has a very strong effect on their bioavailability.

Research activities in 2016/17 


Root plasticity in response to micronutrient deficiencies in barley

In this project we combine microscopic techniques with elemental bioimaging (Laser Ablation-Inductively Coupled Plasma Mass Spectrometry; LA-ICP-MS), in order to document how plant roots anatomically adapt to changing nutrient treatments and how these changes affect ion transport. Presently we focus on micronutrient deficiencies in barley. Researchers: Anle Chen, Daniel P. Persson and Søren Husted. Contact: shu@plen.ku.dk

The effect of suberin and defective Casparian strips on radial ion transport
Here we work with Arabidopsis mutant with defective Casparian strips and suberin development, in order to understand the role of the endodermis for the control of radial ion transport. Researchers: Daniel P. Persson, Anle Chen and Søren Husted. Contact: dap@plen.ku.dk

Iron and Zn speciation in cereal grain tissues: Understanding the chemistry behind bioavailability of iron and zinc
In this project we mainly use liquid chromatography coupled to ICP-MS in order to analyze the iron and zinc speciation in various cereal grain tissues. We also mimic the human digestion system for speciation studies which may explain the chemistry controlling bioavailability. Researchers: André Macherius, Daniel P. Persson and Søren Husted. Contact: macherius@plen.ku.dk


Publications:

  • Simultaneous iron, zinc, sulphur and phosphorus speciation analysis of barley grain tissues using SEC-ICP-MS and IP-ICP-MS: D. P. Persson, T. H. Hansen, K. H. Laursen, J. K. Schjoerring and S. Husted, Metallomics, 1, 418-426 (2009)
  • The role of atomic spectrometry in plant science (review): S. Husted, D. P. Persson, K. H. Laursen, T. H. Hansen, P. Pedas, M. Schiller, J. N. Hegelund and J. K. Schjoerring, Journal of Analytical Atomic Spectrometry (JAAS),26, 1, 52-79 (2011)
  • Metal Binding in Photosystem II Super- and Subcomplexes from Barley Thylakoids: S. Birkelund Schmidt, D. P. Persson, M. Powikrowska, J. Frydenvang, J. K. Schjoerring, P. E. Jensen, and S. Husted. Plant Physiology; 168, 4, 1490-U1718 (2015)
  • Molecular speciation and tissue compartmentation of zinc in durum wheat grains with contrasting nutritional status: D. P. Persson, T. C. de Bang, P. R. Pedas, U. B. Kutman, I. Cakmak, B. Andersen, C. Finnie, J. K. Schjoerring and S. Husted. New Phytologist, 211, 4, 1255-1265 (2016)
  • Multi-element bioimaging of Arabidopsis thaliana roots: D. P. Persson, A. Chen, M. G.M. Aarts, D. E. Salt, J. K. Schjoerring and S. Husted. Plant Physiology, Breakthrough Technologies, doi:10.1104/pp.16.00770 (2016)