Rice paddy Nitrospirae encode and express genes related to sulfate respiration: proposal of the new genus Candidatus Sulfobium.

Rice paddy Nitrospirae encode and express genes related to sulfate respiration: proposal of the new genus Candidatus Sulfobium. Appl Environ Microbiol. 2017 Dec 15;: Authors: Zecchin S, Mueller RC, Seifert J, Stingl U, Anantharaman K, von Bergen M, Cavalca L, Pester M Abstract Nitrospirae spp. distantly related to thermophilic, sulfate-reducing Thermodesulfovibrio species are regularly observed in environmental surveys of anoxic marine and freshwater habitats. Here, we present a metaproteogenomic analysis of Nitrospirae bacterium Nbg-4 as a representative of this clade. Its genome was assembled from replicated metagenomes of rice paddy soil that was used to grow rice in the presence and absence of gypsum (CaSO4×2H2O). Nbg-4 encoded the full pathway of dissimilatory sulfate reduction and showed expression thereof in gypsum-amended anoxic bulk soil as revealed by parallel metaproteomics. In addition, Nbg-4 encoded the full pathway of dissimilatory nitrate reduction to ammonia (DNRA) with expression of its first step being detected in bulk soil without gypsum amendment. The relative abundance of Nbg-4 was similar under both treatments indicating that it maintained stable populations while shifting its energy metabolism. Whether Nbg-4 is a strict sulfate reducer or can couple sulfur oxidation to DNRA by operating the pathway of dissimilatory sulfate reduction in reverse could not be resolved. Further genome reconstruction revealed the p...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research