Nitrite-oxidizing activity responds to nitrite accumulation in soil

作者：Giguere Andrew T^*; Taylor Anne E; Myrold David D; Mellbye Brett L; Sayavedra Soto Luis A; Bottomley Peter J

来源：FEMS Microbiology Ecology, 2018, 94(3): fiy008.

DOI：10.1093/femsec/fiy008

• nitrite
• nitrification
• ammonium
• nitrite-oxidizing bacteria
• soil

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 NO(2)(-)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 NO(2)(-)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 (K-m) 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.

• 出版日期2018-3