The detritusphere as the biogeochemical interface for bacterial and fungal degradation of MCPA

Principle investigators: Prof. Dr. E. Kandeler, Prof. Dr. T. Streck
Co-workers: Dipl. agr. biol. F. Lang, Dipl.-Ing. H. Pagel, Dr. C. Poll


The detritusphere is an excellent model to study microbial-physicochemical interactions during degradation of the herbicide MCPA. While during the first phase of SPP 1315 we focused on bacterial and fungal abundance at the soil-litter interface and carbon flow between different compartments, the second phase will be devoted to elucidating complex regulation mechanisms of MCPA degradation in the detritusphere: (1) At the cellular level, co-substrate availability and laccase abundance might be important regulators, (2) at the community level, bacteria harbouring different classes of tfdA genes might control degradation of MCPA and (3) at the microhabitat level, interaction between MCPA degraders and organo-mineral surfaces as well as transport processes might be important regulators. The concept of hierarchical regulation of MCPA degradation will be included into the modelling of small-scale microbial growth, MCPA transport and MCPA degradation near the soil-litter interface.

Methods:
quantitative PCR (abundance of MCPA degraders and of bacterial taxa)
pyrosequencing (diversity of MCPA degraders)
enzyme activities (e.g. laccase)
isotopes (14C, degradation kinetics)
HPLC (MCPA)

Cooperations within the SPP 1315:
M. Schloter (TU München)
I. Kögel-Knabner (TU München)