Spatial and temporal characteristics of community structure of nitrite-dependent anaerobic methane-oxidizing bacteria in paddy soil

TIAN Mao-hui;SHEN Li-dong;LIU Xin;YANG Wang-ting;JIN Jing-hao;YANG Yu-ling;LIU Jia-qi;School of Applied Meteorology, Nanjing University of Information Science and Technology;

M.oxyfera-like bacteria;;community composition;;diversity;;abundance;;spatiotemporal distribution;;paddy soil

Paddy fields are one of the most important methane sources, which have great impacts on climate change. The nitrite-dependent anaerobic methane oxidation, by NC10 phylum bacteria-Candidatus Methylomirabilis oxyfera(M. oxyfera)-like bacteria, is a new process regulating methane emission from paddy fields. However, little is known about the spatial and temporal variations of M. oxyfera-like bacterial communities and the regulating factors in paddy soils. We investigated the community composition, diversity, and abundance of M. oxyfera-like bacteria in 0-40 cm depth of paddy soils at key growth stages of rice, including tillering, jointing, flowering, and milky stages. Results of high-throughput sequencing showed that community composition of M. oxyfera-like bacteria differed significantly among different soil layers, while no significant variation was observed among different rice growth stages. The diversity of M. oxyfera-like bacteria increased with soil depth. Real-time quantitative PCR showed that the 16 S rRNA gene abundance of M. oxyfera-like bacteria ranged from 5.73×10~6 to 2.56×10~7 copies·g~(-1)(dry weight), with the highest gene abundance in the 10-20 cm layer. Further, the abundance of these bacteria showed a decreasing trend with rice growth. Soil organic carbon content and soil pH were correlated with the M. oxyfera-like bacterial community structures and abundance. In all, our results suggested a certain degree of heterogeneity of spatial and temporal distribution of M. oxyfera-like bacterial communities in paddy soils, which was largely influenced by soil organic carbon and soil pH.