Effects of Veterinary Medicines on the Structural Diversity of the Microbial Community in the Rhizosphere under the Impact of temporal Moisture Gradients- GradMic

• Applicant: Professor Dr. Sören Thiele-Bruhn
• Subject Area: Soil Sciences
• Term: from 2011 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5471428

Medicinal antibiotics exert adverse effects on soil microbial biomass, activity, structural and functional diversity, and resistance level on a mid-term of weeks to months. By FOR566 this was confirmed for the field scale and at field conditions. However, environmental variables, especially soil moisture, alter the antibiotic effect to a yet unknown extent, hampering data interpretation. In the rhizosphere, representing a hot-spot of microbial abundance and activity, effects on structural diversity were determined when targeting specific microbial groups. Furthermore it was found that the specific investigation of root sections is required to unravel effects of antibiotics in this heterogeneous micro-habitat. Hence, it is proposed to investigate effects of sulfadiazine (SDZ) on the soil microbial community structure with special regard to (A) the impact of temporal moisture gradients and rewetting on the susceptibility of the microbial community and (B) effects of SDZ in rhizosphere soil and at the rhizoplane of apical vs. mature root sections. This will be done in a threefold approach by: (i) characterization of the temporal dynamics of antibiotic effects modulated by moisture gradients by intensive time resolved sampling, (ii) obtaining qualitative insights into effects on community structure through in-creased analysis on a group-specific level, and (iii) quantitative investigation of effects on community structure using real-time PCR.

• DFG Programme: Research Units
• Subproject of: FOR 566: Veterinary Medicines in Soils: Basic Research for Risk Analysis