Dr. Moritz Sexauer

Dr. Moritz Sexauer

Julius-von-Sachs-Institut für Biowissenschaften
Lehrstuhl für Botanik II
- Ökophysiologie der Pflanzen -
Julius-von-Sachs-Platz 3

D - 97082 Würzburg

Tel.: +49 (0) 931 31 85065
 

moritz.sexauer@uni-wuerzburg.de

Raum: OG 106

Research Focus

Root nodulation symbiosis: ensuring a good bargain

How plants balance their diet: genetic control of nitrogen foraging

The role of small RNAs in systemic communication in plant symbiosis and development

The roots of root symbiosis

Legumes - pioneers and survivors under extreme conditions

Research interests

Nitrogen is the most important macronutrient in a plants diet. Although ~80 % of our atmosphere consists of elemental dinitrogen, plants cannot utilize it and rely on nitrogen in form of mostly nitrate, ammonia or other organic compounds, which are usually taken up by the plant roots. The availability of soil nitrogen is therefore a major growth limiting factor, shaping occurring plant communities. However, most Legumes and some members of the related Fagales, Cucurbitales and Rosales lineages are able to establish symbiotic relations with rhizobial bacteria, respectively Frankia to fix aerial nitrogen, to overcome such soil limitations.

As beneficial as this symbiosis seems at first glance, the symbiotic nitrogen fixation and the accommodation of bacteria is an energy and resource intense process for the plant. Because of this Legumes regulate their symbiosis precisely, according to their nitrogen demand and nitrate availability in a process called Autoregulation of Nodulation (AON). Beyond this also the availability of other macro and micronutrients, the plants development and energy status, as well as other abiotic and biotic factors shape the establishment of the symbiosis as well as its upkeep.

In my research I’m interested in how legumes adapt their symbiosis according to different biotic and abiotic cues in an ever changing growth environment.

Comparing the evolutionary young nitrogen fixing symbiosis and the ancestral root developmental programs and arbuscular mycorrhiza symbiosis, we hope to gain insight into how the nitrogen fixing symbiosis evolved and which steps were crucial in its evolutionary success.

In this context I’m interested in the role of systemic micro RNAs and transcriptions factors driving the plants adaptations to abiotic and biotic cues. To address these questions, I mainly utilize the model plant Lotus japonicus and its endosymbiont Mesorhizobium loti.