Uwe Ludewig and the future of agricultural crops
Prof. Dr. Uwe Ludewig has been head of the Department of Nutritional Crop Physiology at the University of Hohenheim for around a year now. Physicist by training and specialist in electrophysiology, Prof. Ludewig now works mainly on transport processes in plants. He plans to use molecular relationships to enhance the potential of agricultural crops, reduce the use of fertilisers and make agricultural plants fit for climate change.
Uwe Ludewig developed an interest in biology during his studies at the University of Göttingen where he also touched on biophysics. He did his degree thesis at the Max Planck Institute for Biophysical Chemistry in the group of Nobel Laureate Prof. Dr. Erwin Neher where he focused on the investigation of ion channels in cell membranes, which gave him deeper insights into electrophysiology. Erwin Neher and Bert Sakmann developed the patch-clamp technique that is a prerequisite for studying ion channel transport mechanisms, and were awarded the Nobel Prize in Physiology or Medicine in 1991 for their discoveries concerning the function of single ion channels in cells. By this point, Ludewig was fascinated by the subject, and he continued his academic career with doctoral studies under the supervision of another famous electrophysiologist: Gotthilf Wilhelm Leibniz prizewinner Prof. Dr. Dr. Thomas Jentsch at the University of Hamburg. From 1993 to 1996, Ludewig focused mainly on the transport processes of chloride channels and their role in physiological processes.
Ludewig accompanied his doctoral studies with training in biology. “Back then, the University of Hamburg offered special courses for non-biologists. One of these courses gave me a certificate in molecular biology,” said Ludewig. Armed with excellent degrees, training and an EMBO grant, Ludewig went to the University of Seville, Spain, to work as electrophysiologist. He decided to stay in Europe as “Europe is home to outstanding biophysics research groups, which are excellent alternatives to spending a year or so in the USA, something that has become kind of obligatory.”
Immobile but well-nourished– the secrets of plant physiology
Ludewig’s main interests lie in transport processes in all organisms, including humans, animals and plants. After he had worked with rats for a while, he decided to switch to plants. “I was extremely interested in the way plants control the transport of metabolites and minerals. Some trees reach up to 600 years of age; they always stay in the same place.” Ludewig moved on to the University of Tübingen where he sought to find answers to the following questions: How do trees get enough nutrients and survive hundreds of years? How do they control the uptake of nutrients? He characterised the transport complexes of plants, which he transferred into frog eggs using molecular biology methods. “Frog oocytes are an excellent expression system that is easy to handle due to the size of oocytes, which are around one millimetre in diameter,” explained Ludewig.
In 2002, Ludewig established his own research group on the molecular physiology and the electrophysiology of nitrogen transport. The researchers from Tübingen worked mainly with Arabidopsis, an inconspicuous weed that has become a widely-studied laboratory plant around the world. “A lot is known about Arabidopsis, making the plant excellently suited for investigating fundamental aspects,” said Ludewig. After his habilitation and temporary professorship at the Technical University of Darmstadt, Ludewig was appointed head of the Department of Nutritional Crop Physiology at the University of Hohenheim where he has been researching and teaching since late October 2010.
Focus on agricultural crops
Ludewig’s move to Hohenheim was also associated with a shift towards agricultural crops. “I am very happy to have chosen to work on agricultural crops because it is important not to work exclusively with model plants. Many people thought that the molecular mechanisms of model plants could be easily transferred to the situation in agricultural crops, but this is not at all the case.” Ludewig now plans to focus on issues that are relevant to feeding the growing world population because he believes that this is a largely neglected issue in basic research. “We know a great deal about how the nutrition of plants works. However, the changing climate comes with new challenges, especially as far as the cultivation of agricultural plants is concerned. We would like to find out how plants change their nutrition under changing environmental conditions that imply less water and higher temperatures.”
The researchers need to obtain insights into fertilisation, and Ludewig's specific area of interest relates to previous work he has done on the uptake and processing of nitrogen in plants. “Nitrogen-rich fertiliser has been used enormously for many decades. And nitrogen is known to contribute to global warming. We plan to investigate whether and how we can improve plants’ potential to effectively use nitrogen; the way to do this is by breeding effective nitrogen users. The supply of nutrients can also be improved by combining fertilisers with other substances; some minerals and micronutrients are known to improve plants’ ability to take up nutrients. The researchers from Hohenheim are currently focusing on the substances and concentrations that they need to achieve this.
Ludewig also focuses on traditional phosphate fertilisation. “I believe that the majority of suitable phosphate sources will be depleted in around 100 years. We therefore need to focus now on the development of alternative strategies. I am thinking, for example, of precipitation products that arise in sewage treatment plants; these materials can be used as sources of phosphate,” said Ludewig. In general, Ludewig foresees a paradigm shift in the field of agriculture. “Over the last 30 or 40 years or so, scientists have been mainly focused on achieving the highest possible yield. Nowadays, we are more concerned about ways of eating more healthily. In addition, the global population is growing and requires increasing quantities of food. The question therefore arises as to how we will be able to live on well-nourished plants,” said Ludewig, outlining his future research plans.
Energy crops – an interesting option for nutrient-poor soils
Ludewig has more than the nutrition of the global population in mind when he looks at agricultural crops. He is also focused on the use of crops for the production of energy. He uses Miscanthus, also known as giant Chinese silver grass, to find out whether and how energy crops can be grown at locations that are not really suitable for the cultivation of food plants. “Miscanthus is an interesting candidate because it is a plant that does not require large amounts of nutrients and water. These characteristics make Miscanthus an ideal plant for fertile soil as well as for locations that have hardly, or not at all, been used up until now for the cultivation of plants. “We are still working on finding out whether the plant is able to grow in very dry areas,” said Ludewig highlighting a project he is working on in collaboration with Prof. Dr. Iris Lewandowski, head of Renewable Raw Materials and Bioenergy Plants at the University of Hohenheim.
One of Ludewig’s main goals in his research into energy crops is to achieve a situation where as many mineral substances as possible remain in the soil, i.e. work with plants that use the nutrients contained in the soil for their growth but which release these substances into the soil once they are no longer needed. “We hope that as many nutrients and minerals as possible are retained in the soil when the plants are harvested. As far as energy plants are concerned, we are only interested in plant carbon compounds that can be used for the generation of energy,” said Ludewig. This can only be achieved by rethinking and further developing the current breeding options. Genetic engineering could be an option, but not for Ludewig who does not believe that genetically modified plants will be widely accepted in Germany in the near future.
University of Hohenheim
Institute of Crop Science
Prof. Dr. Uwe Ludewig
Tel.: +49 (0)711 459-22344