Michael Broberg Palmgren
Thorvaldsensvej 40, Frederiksberg C
· Biological pumps found in plants
Pumps actively transport ions or molecules across biological membranes. Our goal is to learn how such pumps function, how they are regulated, and what their physiological roles are.
P-type ATPases form a large family of pumps in plants. P-type ATPases are fueled by ATP and catalyze the transport of a cation or a phospholipid from one side of a lipid bilayer membrane to the other. The P in P-type indicates that these pumps form a phosphorylated reaction cycle intermediate. In plants, there are different P-type pumps pumping protons, calcium, heavy metals and phospholipids. P-type pumps that we study are, amongst other functions, essential for growth, nutrient uptake, stress tolerance, vesicle formation in the secretory pathway and signal transduction.
Knowledge gained from studying P-type pumps in the model plant Arabidopsis thaliana is translated to the model cereal crop barley. The goal is to develop crops that require less input and give more output. There is an urgent need to reduce the use of fertilizers and water that are not only precious resources but also causes of pollution and salinization. We also need to preserve the nature we have left, and future food and feed production should not depend on bringing more land under the plow.
· Accelerated domestication of orphan crops and wild plants
Nine plant species provide almost all the world’s food intake, and all are refined. By comparison, there are about 380,000 wild plant species. Nature therefore offers us huge genetic variation that we do not exploit today. Instead of trying to make highly domesticated plants more robust, our research addresses how to harness the hardiness of wild plants as a starting-point to make crops that are resilient to diseases, nutrient shortage and extreme weather events.
All cereal crops today are annual grasses with weak root systems. In contrast, perennial grasses have deep and long lasting root system that binds large amounts of carbon and are very efficient in taking up nutrients and water. Still, perennials have not been domesticated to a degree so that they can compete with annuals. We work to accelerate domestication of perennial wheatgrass (Thinopyrum intermedium) to make it a climate-friendly and sustainable of food and feed.
Quinoa (Chenopodium quinoa) is a nutritious minor crop that tolerates drought and salinity better than most other crops. Although quinoa has yet to reach its potential as a fully domesticated crop, breeding efforts to improve the plant have been limited. Molecular and genetic techniques combined with traditional breeding are likely to change this picture. We work to decipher the molecular mechanisms underlying water stress tolerance in plants, and generate a knowledge base and procedure for breeding of this and other drought-tolerant crops.
· Why do plants not have sodium pumps and would they benefit from having one?
The cell membrane of plants is energized by proton pumps, that extrude positive charge from the cell and acidify its exterior, whereas animal cells are energized by pumps that extrude sodium ions. One important consequence is that most plants have difficulties dealing with sodium, . This becomes a problem in agriculture where continued irrigation leads to increased salinization of soils.
Attempts to generate salt-tolerant plants have focused on increasing the expression of or introducing salt stress-related genes from plants, bryophytes and yeast. Even though these approaches have resulted in plants with increased salt tolerance, plant growth is decreased under salt stress and often also under normal growth conditions. New strategies to increase salt tolerance are therefore needed. Theoretically, plants expressing an animal-type Na+/K+-ATPase should not only display a high degree of salt tolerance but should also reduce the stress response exhibited by the first generation of salt-tolerant plants under both normal and salt stress conditions.
We investigate the evolution of the plant bioenergetics system and investigate whether proton and sodium pumps can co-exist in the same cell type. This also allows for testing whether plants can be made more tolerant to salt stress.
See also: http://www.traplabs.dk
Professor i Plantefysiologi ved Institut for Plante- og Miljøvidenskab, Københavns Universitet
2003: dr. scient., KVL
1990: fil. dr. (ph.d.) i Plant Biochemistry, Lunds Universitet
1987: cand. scient. i Molecular Biology, Københavns Universitet
1998-nu: Professor, Institut for Plantebiologi og Bioteknologi, Det Biovidenskabelige Fakultet, Københavns Universitet (tidligere KVL)
2004-05: Institutleder, Institut for Plantebiologi, KVL
2002: Visiting Professor, CNRS, Univ. Pierre et Marie Curie, Paris
1995-1997: Lektor, Molekylærbiologisk Institut, Københavns Universitet
1993-1995: Adjunkt, Institut for Plantebiologi, KVL
1992: EMBO Long-term Fellow, August Krogh Instituttet, Københavns Universitet
1990-1991: EMBO Long-term Fellow, EMBL, Heidelberg