Response of denitrification genes nirS, nirK, and nosZ to irrigation water quality in a Chinese agricultural soil

Abstract

Purpose Denitrification is an important biochemical process in global nitrogen cycle, with a potent greenhouse gas product N 2 O. Wastewater irrigation can result in the changes of soil properties and microbial communities of agricultural soils. The purpose of this study was to examine how the soil denitrification genes responded to different irrigation regimes. Materials and methods Soil samples were collected from three rural districts of Beijing (China) with three different irrigation regimes: clean groundwater (CW), reclaimed water (RW), and wastewater (WW). The abundance and diversity of three denitrification microbial genes (nirS, nirK, and nosZ) were examined by real-time polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) molecular approaches. Results and discussion The abundance of nirS in the WW treatment was higher than that in the CW treatment, and no significant difference was found between the RW and CW or WW treatments. The abundance of nirK gene of the RW and WW treatments was higher than that of the CW treatment. There was no difference for nosZ gene among the three treatments. Correspondence analysis based on the DGGE profiles showed that there was no obvious difference in the nosZ gene composition, but nirS and nirK genes changed with different irrigation regimes. Conclusions Irrigation with unclean water sources enhanced the soil NO 3 − content and changed the abundance and composition of soil denitrifiers, and different functional genes had different responses. Irrigation with unclean water sources increased the abundance of nirK gene and changed the community structures of nirS and nirK genes, while nosZ gene was relatively stable in the soil. These results could be helpful to explore the mechanisms of the variation of denitrification processes under long-term wastewater irrigation and partially explain the reason of more N 2 O output in the field with wastewater irrigation.

Denitrification potential under different fertilization regimes is closely coupled with changes in the denitrifying community in a black soil

“…Correspondingly, niche differentiation between nirS-and nirK-type denitrifiers has been proposed to explain the distinct behaviors of these two nir-harboring guilds (Hallin et al 2009;Chen et al 2010;Enwall et al 2010;Jones and Hallin 2010), and our findings support this. However, the response pattern of nirK denitrifiers in this study was different from previous reports where nirK denitrifiers were more responsive to different fertilization regimes and environmental changes than nirS denitrifiers (Yoshida et al 2010;Chen et al 2010;Zhou et al 2011). Hence, based on these, in combination with the particular native edaphic properties including temperature and soil cultivation history, which both have been demonstrated to influence the denitrifiers' community (Braker et al 2010(Braker et al , 2012Enwall et al 2010), a soil-specific intrinsic denitrifier community or distinct denitrifiers' population responding to fertilization in this soil type was expected.…”

The Abundance of Fungi, Bacteria and Denitrification Genes during Insect Outbreaks in Scots Pine Forests

“…For example, nirK proved to be more responsive to changes such as land use practices [46], vegetation cover [47], and water source quality [48], compared to nirS. Furthermore, nirK has a higher sensitivity towards nutrient additions than nirS [23,49].…”

Response of ammonia-oxidizing archaea and bacteria to long-term industrial effluent-polluted soils, Gujarat, Western India

“…Translated amino acid sequences (for both AOA-amoA and AOB-amoA genes) were used to construct neighbor-joining tree followed by Poisson model with 1,000 replicates to produce bootstrap values. Diversity indices such as Shannon index (H) and Evenness index (E) were measured as described in our earlier articles (Shen et al 2008;Zhou et al 2011).…”