Dr. Hannes Schmidt

Former Postdoc at DOME
Now: Senior Scientist at TER
University of Vienna
Department of Microbiology and Ecosystem Science
Althanstrasse 14
A-1090 Vienna

Research Interests

My current research aims at investigating the identity, activity, and spatial distribution of nitrogen-fixing microbes (diazotrophs) associated with wetland rice. Diazotrophs represent the only biological means to make atmospheric nitrogen (N) accessible to rice plants, and thus have the power to alleviate N-shortage in rice cultivation which is conventionally managed via costly and environmentally hazardous fertilization. Plant-soil interfaces in waterlogged rice fields comprise highly dynamic environments where strong gradients occur within short distance from active roots (e.g. carbon, oxygen; Figure 1). Consequently, I am especially interested in understanding the formation of niches and the differentiation of associated diazotroph communities in paddy soil - rice root microenvironments. Furthermore, our knowledge of in situ single-cell activities and potential sites of N-transfer between diazotrophs and rice plants is currently very limited and we seek to unravel these processes in the course of my projects. We apply a multidisciplinary approach combining tools of molecular biology, biogeochemical assays, microscopy, and single-cell isotope analysis techniques to comparatively investigate the community structures, colonization patterns, and in situ N fixation rates of diazotrophs in paddy soil - rice root microenvironments.

Moreover, I am generally interested in how plants, microbes, and soil interact on a microscale with a special interest in techniques capable of visualizing underlying processes. In situ hybridization techniques (CARD-FISH, Gold-FISH) help me to visualize single microbial cells of interest associated with roots and to investigate colonization patterns such as potential preferential aggregation of cells around root morphological structures (Figure 2). Other in situ techniques such as planar optodes provide information on oxygen and pH gradients in microenvironments and together with information on associated microbiomes will help me to understand the drivers of community structure, microbial spatial distribution, and interactions among plants, microbes, and soil.

Research Projects

Understanding the micro-environments of diazotrophs and their associated activities in rice