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

药用抗生素对土壤微生物生物量、活性、结构和功能多样性以及抗性水平的影响在中期可达数周至数月。根据FOR566，这一点在田间规模和田间条件下得到确认。然而，环境变量，特别是土壤湿度，在未知的程度上改变了抗生素的影响，阻碍了数据解释。在根际，代表着微生物丰度和活性的热点，当针对特定的微生物组时，确定了对结构多样性的影响。此外，还发现需要对根部切片进行具体调查，以揭示抗生素在这种异质微生境中的影响。因此，建议研究磺胺嘧啶(SDZ)对土壤微生物群落结构的影响，特别是(A)时间水分梯度和复湿对微生物群落敏感性的影响和(B)SDZ在根际土壤和根尖与成熟根段根面的影响。这将通过三种方法来完成：(I)通过密集的时间分辨采样来表征受水分梯度调制的抗生素效应的时间动态，(Ii)通过在特定群体水平上的增量分析来获得对群落结构的影响的定性见解，以及(Iii)使用实时荧光聚合酶链式反应(Real-Time-PCR)对群落结构的影响进行定量研究。

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.