| Dallinger, A; Horn, MA: Agricultural Soil and Drilosphere as Reservoirs of New and Unusual Assimilators of 2,4-Dichlorophenol Carbon, Environmental Microbiology, 16, 84-100 (2014) | |
| Abstract: 2,4-Dichlorophenol (2,4-DCP) is a potential soil and groundwater contaminant. Earthworms modulate growth and activities of soil microbiota. Thus, active 2,4-DCP degraders in agricultural soil and drilosphere (i.e., burrow walls, gut content, and cast) were identified by comparative amplicon pyrosequencing based 16S rRNA stable isotope probing (CAP-SIP) in soil columns. In situ relevant concentrations of [U-13C]2,4-DCP were consumed in soil within 19 and 41 days in the presence and absence of the endogeic earthworm Aporrectodea caliginosa, respectively. [U-14C]2,4-DCP mineralization was higher in cast, burrow wall, and soil from columns with than without earthworms. [U-14C]2,4-DCP mineralization was lowest in gut contents. Data indicated a strong impact of earthworms on the active microbial community. Novosphingobium, Comamonas, and Desulfitobacterium sp. assimilated 2,4-DCP-[13C] in the absence of earthworms. Pseudomonas, Flavobacterium, and Clostridium sp. assimilated 2,4-DCP-[13C] in the drilosphere. Novosphingobium and Variovorax related taxa dominated [U-13C]2,4-DCP consumers in soil slurries with drilosphere and bulk soil material. 16S rRNA sequences suggested species level novelty. The collective data demonstrates that new Bacteroidetes and Alpha-/Betaproteobacteria were involved in 2,4-DCP-C transformation, and indicated that diverse and hitherto unknown microbes associated with carbon flow from 2,4-DCP are shaped by earthworms. |
