Nitrite-oxidizing activity responds to nitrite accumulation in soil

FEMS Microbiol Ecol. 2018 Mar 1;94(3). doi: 10.1093/femsec/fiy008.

Abstract

The factors influencing how soil nitrite (NO2-)- and ammonia (NH3)-oxidizing activities remain coupled are unknown. A short-term study (<48 h) was conducted to examine the dynamics of NO2--oxidizing activity and the accumulation of NO2- in three Oregon soils stimulated by the addition of 1 mM NH4+ in soil slurry. Nitrite initially accumulated in all three soils; its subsequent decline or slowing of the accumulation of the NO2- pool by 24 h was accompanied by an increase in the size of the nitrate (NO3-) pool, indicating a change in NO2- oxidation kinetics. Bacterial protein synthesis inhibitors prevented the NO2- pool decline, resulting in a larger accumulation in all three soils. Although no significant increases in NO2--oxidizing bacteria nxrA (Nitrobacter) and nxrB (Nitrospira) gene abundances were detected over the time course, maximum NO2- consumption rates increased 2-fold in the treatment without antibiotics compared to no change with antibiotics. No changes were observed in the apparent half saturation constant (Km) values for NO2- consumption. This study demonstrates phenotypic flexibility among soil NO2- oxidizers, which can undergo protein synthesis-dependent increases in NO2- consumption rates to match NH3 oxidation rates and recouple nitrification.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Ammonia / metabolism
  • Bacteria / metabolism*
  • Nitrification
  • Nitrites / analysis
  • Nitrites / metabolism*
  • Nitrobacter / metabolism
  • Oregon
  • Oxidation-Reduction
  • Soil / chemistry
  • Soil Microbiology

Substances

  • Nitrites
  • Soil
  • Ammonia