Allan Rasmusson

I was born in 1965 and grew up in the Skåne countryside. Among many interests, biology took over during the studies at Lund University. In my degree project at Imperial College, London, I became interested in plant respiration and energy efficiency. This, I have further investigated as a graduate student in Lund and Adelaide, as PostDoc at the Institut für Genbiologische Forschung Berlin, and since 1996 as reasearcher at Lund University. Gradually, I changed methodologies, biochemical, molecular biological and physiological, and I have had the pleasure of being part of how plant respiration over time has proven to be involved in many fundamental life processes, developing a more integrated view of plant metabolism. With time, the research has lead to new topics mainly relating to the control of whole cell redox levels and plant acclimation to soil pH, nitrogen and fungal symbionts.

Research

Plants form most of the nature we see as well as the economic (esp. nutritional) basis of the human civilisation. With their lifestyle of combining light, carbon dioxide, water and nutrients, plants are set in a hostile highly variable environment, yet they are specialised in managing it there. A plant contains some 30000 genes, and a cell of any particular organ or tissue will contain roughly 10000 proteins, interacting with each other, with the DNA, RNA, lipids, carbohydrates and hundreds of metabolites, across several cellular compartments. Roughly, half of the genes we do not know the function for. This is an overwhelming complexity. Generally, even the "simpler" of the plants are seen to contain a large set of compartmental and chemical redundancy in many steps of the basic and specialised life processes, ie. things can take different paths leading to "almost" the same end. This appears to give plants an enormous internal flexibility that allows them to manage the stressful changes that occur in their habitat (wind, light and UV variations, water supply variations, pathogens etc.). Clearly, key factors for how plants manage to grow in a hostile environment resides in their internal complexity and layers of protection mechanisms. For understanding plant function as a whole it is important that we understand in detail a few selected wild reference species like for example Arabidopsis thaliana. These provide mechanisms and models that can be translated to species that are harder to study. One of the most central nodes of plant function is the distribution of energy and redox via NADPH and NADH, because this connects both to growth and to the many systems that protect plants. Also, NADPH and NADH are central components in the cytosolic metabolic pathways, which connect the two largest biochemical processes on earth, photosynthesis and respiration in plants. Especially the latter has been difficult to predict in relation to CO₂ concentrations in the atmosphere, and another mind-thrilling issue is that a substantial part of plant respiration takes place via the “wasteful” energy-bypass pathways. To be able to discretely modify these central functions by modifying the energy-bypass pathways gives us a possiblity to address the balancing between the different life functions of plants. A second central issue lies in the functions of the biological membranes. How they delineate compartments and form complexity in the cell. Their integrity is essential for life functions, yet they are exposed and dynamic. Membranes are targets for destruction or modification by competing species, pathogens and abiotic stress conditions in all organisms. Yet among the large number of different molecules making up a membrane relatively little is known about which of them carry protective functions and how they work together. Among thousands of antimicrobial peptides, we found that the most studied membrane-attacking type is beeing actively counteracted by plant cells. Identifying the membrane components needed for protection against this peptide type can therefore clarify how a complex vulnerable structure can be modified to be fit for a different functional scenario.

Plant interactions with antimicrobial peptides (PIs S. Widell and A. Rasmusson):

Membrane-active antimicrobial peptides permeabilise susceptible cells and take part in pathogenicity, pathogen defence and competition between organisms. We study a unique system of induced plant resistance to a membrane-active peptide . This peptide is produced by the plant symbiont Trichoderma viride to attack bacteria and other fungi. This should light on how antimicrobial peptides can be specific for certain membranes, which is little known. The project is relevant for future use of Trichoderma for biocontrol of pathogens, but also for medicin where a new antibiotics and their target specificities need to be investigated.

Cell redox control under plant stress (PI A. Rasmusson):

NAD(P)H status and respiratory rate and -metabolite levels strongly correlate to plant growth yield, but the functional background is not clear. A need for supply of reduced nicotinamide nucleotides (NADPH and NADH), and in reverse, for their rapid reoxidation, should vary substantially between different stress and growth situations. Plant stress already imposes the largest restriction on agriculture worldwide. Biotechnological modifications of plants have improved stress tolerance and development of plants for production, but a major hinder for further development is a lack of knowledge on metabolic systems. Therefore we have developed plants with modified reduction levels for NADH and NADPH. These we now analyse to determine how these changes affect metabolism, growth and especiall, tolerance to external stress. Apart from addressing the central scientific issues of how cells manage and utilise changes in redox, increased knowledge on energy and redox metabolism in model plants is expected to induce long-term improvements on how food and energy crops can counteract stresses, as well as by increasing the accuracy of models for global respiration.

Future projects:

When technology allows it, I would like to directly test if particular plant components have a principal function in controlling temporal internal fluctuations.

The ultimate goal would be to develop concepts of how associations of biomolecules temporally and spatially counteract the changes induced by environmental stresses, and how to control whole pathways for mastering plant outcomes.

Education

I am deeply involved in several courses, at basic and advanced level. Major assignments (including course design, coordination and much of the teaching) include the 15 credits advanced course in Plant Biology, the 15 credits basic course in Molecular Biology, and the 15 credits advanced course in Methods in Molecular Biology. I also teach smaller parts of the 12 credits basic course in Botany, and the 15 credits advanced courses in Molecular Genetics and Molecular Genetics of Eukaryotic Organisms.

Within postgraduate training, I co-organise the 1-week methods course Quantitative PCR Methods within the Postgraduate Courses in Life Science program.

In both undergraduate and postgraduate education I supervise and examine projects.

Connected to education, I am also involved in literature development, being principal contributor to three editions of the internationally dominant textbook of Plant Physiology (Taiz and Zeiger, Plant Physiology), which has been issued in eleven different languages.

Skills and Knowhow

Major methodological skills: Plant growth and treatment on soil and in sterile culture, construction and analysis of genetically modified plants, quantitative mRNA and transcriptome analysis, organelle isolation and analysis, immunological protein analysis, combining multiple levels of analysis. Major theoretical expertise: Plant physiology, plant central metabolism and energy transduction, membrane functions and molecular process regulation via gene expression.

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