Nov 3, 2010

Archaea rather than bacteria control nitrification in two agricultural acidic soils

FEMS Microbiology Ecology
Cécile Gubry-RanginJames I Prosser

Abstract

Nitrification is a central component of the global nitrogen cycle. Ammonia oxidation, the first step of nitrification, is performed in terrestrial ecosystems by both ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). Published studies indicate that soil pH may be a critical factor controlling the relative abundances of AOA and AOB communities. In order to determine the relative contributions of AOA and AOB to ammonia oxidation in two agricultural acidic Scottish soils (pH 4.5 and 6), the influence of acetylene (a nitrification inhibitor) was investigated during incubation of soil microcosms at 20 °C for 1 month. High rates of nitrification were observed in both soils in the absence of acetylene. Quantification of respective amoA genes (a key functional gene for ammonia oxidizers) demonstrated significant growth of AOA, but not AOB. A significant positive relationship was found between nitrification rate and AOA, but not AOB growth. AOA growth was inhibited in the acetylene-containing microcosms. Moreover, AOA transcriptional activity decreased significantly in the acetylene-containing microcosms compared with the control, whereas no difference was observed for the AOB transcriptional activity. Consequently, g...Continue Reading

Mentioned in this Paper

Acetylene
Nitrogen Cycle
Hypokinesia
Transcription, Genetic
Archaea
Blood Ammonia Measurement
Ammonia Inhalants
Genes, Bacterial
Nitrification
Sequence Determinations, DNA

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