Genetic Technologies

In our research project, we aim to characterize selected genes in poplars and investigate whether they are involved in the drought stress tolerance of trees. We examine whether an increased expression of a selected gene or the knockout of the gene leads to greater resistance to drought in poplars.

Under controlled greenhouse conditions, numerous measurements can be obtained using invasive (leaves are taken from the tree) and non-invasive methods (leaves remain on the tree), which allow us to track the stress response. In addition to physiological and morphological analyses in the greenhouse, a wide range of molecular physiological analyses will be conducted in the laboratory. Here, we specifically investigate whether the plants experienced oxidative stress, their proline content (a marker for stress response), and how much abscisic acid, a key stress hormone, was produced.

Attached to this work are two Master's theses in cooperation with the universities in Hannover and Hamburg.

Alexander Fendel and Tobias Brügmann have described the conceptualization and evaluation of such stress experiments in an article in the German journal AFZ-DerWald: Fendel A, Brügmann T (2023) "Kontrolliert unter Stress." AFZ Der Wald 78(20):12-15.

European beech trees have a large distribution area. At its southern edge, they are confronted with different climatic conditions than in Germany: the average annual temperature is higher and the amount of precipitation is lower than in Germany. To investigate the different drought stress tolerance of beech provenances, a provenance trial ("climate forest") was planted in Berlin. Here, individual trial members (a group of trees) can be irrigated, while other trial members are affected by the (naturally occurring) drought stress in summer. A drought stress experiment was initiated in the summer of 2022 with one provenance each from Germany, France, Italy and Spain. Ecophysiological, biochemical, and genetic analyses were conducted using different stress intensities. The data will be used to estimate the drought stress tolerance of individual European beech provenances.

Genetic regulations will be investigated by transcriptome analysis. For this purpose, all mRNA molecules produced in the leaves will be decoded. Biochemical analyses include measuring the levels of the drought stress markers proline, malondialdehyde (MDA), and peroxide. Together with physiological data such as photosynthetic activity, stomatal conductance, and water potential, the analytical triad should provide a comprehensive picture of drought stress tolerance.

We expect answers to the questions: What is the response of European beech under drought stress? Do the selected provenances differ in their drought stress response? Which genes are switched on or off and how fast or how strongly is gene activity regulated? Is provenance-dependent differential stress tolerance related to differential gene regulation? The findings from this collaborative research may be helpful in selecting suitable drought-tolerant provenances.

Ecology of Plants, Free University of Berlin (PD Dr. M. Forstreuter)

Plant Biotechnology and Bioinformatics, Braunschweig University of Technology (Prof. Dr. B. Pucker)