Detection of ammonia oxidising archaea (AOA) in New Zealand soils

Recent studies have raised the possibility that members of the archaeal phylum Crenarchaeota have the potential to perform ammonia oxidation in soils, the first and rate limiting step of nitrification, and a function previously thought to be exclusively performed by autotrophic bacteria. These Crenarchaeota are now commonly called ammonia oxidising archaea (AOA). We have applied polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and sequencing techniques to determine whether AOA are present in New Zealand soils. We used three contrasting New Zealand soils (a sandy soil from Manawatu, a gley soil from Northland and a volcanic ash soil from Taranaki). Successful PCR amplification from all the soil DNA confirmed AOA existence in the three soils tested. The DGGE analysis confirmed that AOA present in New Zealand soils are a diverse group. All partial ammonia monooxygenase (AMO) sequences of AOA clones retrieved from this study were similar to already available AMO sequences in the National Center for Biotechnology Information gene database.