Genome sequence of acid tolerant gamma ammonia oxidizing-bacteria. Candidatus Nitrosoglobus terrae

Soil pH is well known to be a limiting factor for nitrification. Generally, nitrification activity shows a positive correlation with soil pH. In soil, the lower limit of pH for nitrification has been considered to be around 4. Autotrophic ammonia-oxidizing bacteria have been considered to be neutrophilic, and their lower limit of growth is around pH 6 in pure culture. On the other hand the nitrification activities in the tea soils were very high despite the low pH. We successfully isolated acid tolerant ammonia oxidizing-bacteria from the tea field soils. The isolated strain (TAO100) was found to belong to gamma-Proteobacteria. The optimum pH for the growth of TAO100 was around 6. The growth was still observed at pH 5 and ceased at around pH 8.0. The aim of this project was to compare the genome sequence of TAO100 with those of neutrophilic ammonia oxidizing-bacteria in order to identify genetic traits that may explain acid adaptation mechanisms. Therefore, we determined the whole genome sequence of TAO100.