Characterization of Fungal -Containing Communities and NO Emission From Fungal Denitrification in Arable Soils

Fungal denitrifiers play important roles in soil nitrogen cycling, but we have very limited knowledge about their distribution and functions in ecosystems. In this study, three types of arable soils were collected across different climate zones in China, including quaternary red clay soils, alluvial soils, and black soils. The composition and abundance of fungal -containing denitrifiers was determined by MiSeq high-throughput sequencing and qPCR, respectively. Furthermore, a substrate-induced inhibition approach was used to explore NO emissions from fungal denitrification. The results showed that the arable soils contained a wide range of -containing fungal denitrifiers, with four orders and eight genera. Additionally, approximately 57.30% of operational taxonomic unit (OTUs) belonged to unclassified -containing fungi. Hypocreales was the most predominant order, with approximately 40.51% of the total number of OTUs, followed by Sordariales, Eurotiales, and Mucorales. It was further indicated that 53% of fungal OTUs were shared by the three types of soils (common), and this group of fungi comprised about 98% of the total relative abundance of the -containing population, indicating that the distribution of fungal -containing denitrifiers was quite homogenous among the soil types. These common OTUs were determined by multiple soil characteristics, while the composition of unique OTUs was manipulated by the specific properties of each soil type. Furthermore, fungal NO emissions were significantly and positively correlated with fungal abundance in the soils, whereas it was not clearly related to fungal compositions. In conclusion, although the arable soils hosted diverse -containing fungal denitrifiers, fungal compositions were highly homogenous among the soil types, which could be a consequence of enduring agricultural practices. The abundance of fungal -containing denitrifiers, rather than their composition, may play more significant roles in relation to NO emission from fungal denitrification.