Carbon substrate selects for different lineages of N2O reducing communities in soils under anoxic conditions

Agricultural soils are a main source of nitrous oxide (N2O), potent greenhouse gas and the dominant ozone-depleting substance emitted to atmosphere. The only known sink N2O in soil is microbial reduction N2. Carbon (C) availability key factor determining community composition soil. However, its role shaping structure reducing communities unexplored. In this study, microcosm experiment was set up which two arable with contrasting edaphic properties were incubated anaerobically for 83 days four different C substrates: glucose, acetate, hydroxyethylcellulose (HEC) mixture three. We show that effect addition on abundance diversity clade I II nosZ genes, encoding variants reductase, varies across substrates differently types, yet still plays an important selecting specific taxa reducers under denitrifying conditions. observed increase betaproteobacterial species HEC, whereas alphaproteobacterial within other Proteobacteria Bacteriodetes associated glucose acetate. These results C-substrates select certain lineages influence patterns niche partitioning clades reducers, factors drive differences between communities.