Nitrospira are more sensitive than Nitrobacter to land management in acid, fertilized soils of a rapeseed-rice rotation field trial

• Published in: The Science of the total environment Vol. 599-600; pp. 135 - 144
• Main Authors: Han, Shun, Luo, Xuesong, Liao, Hao, Nie, Hailing, Chen, Wenli, Huang, Qiaoyun
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-12-2017
• Subjects: Bacteria - metabolism; Brassica rapa - growth & development; China; Conservation of Natural Resources; Fertilizers; Nitrite oxidation (NO); Nitrite-oxidizing bacteria (NOB); Nitrites - metabolism; Nitrobacter - metabolism; Nitrobacter-like NOB; Nitrospira-like NOB; Oryza - growth & development; Oxidation-Reduction; Rapeseed-rice rotation system; Soil; Soil Microbiology; Nitrobacter-like NOB; Rapeseed-rice rotation system; Nitrospira-like NOB; Nitrite-oxidizing bacteria (NOB); Nitrite oxidation (NO)
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2017.04.086

•Straw input and rice-growing stimulate soil nitrite oxidizing potential (NO).•Soil NO is related to a shift in Nitrospira-like NOB community structure.•Nitrospira community shift was significantly affected by pH, NH4+ and moisture.•Nitrobacter-like NOB was just not significantly affected in this system.•Nitrospira are more sensitive to straw input and rice-growing than Nitrobacter.
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Nitrite oxidation is recognized as an essential process of biogeochemical nitrogen cycling in agricultural ecosystems. How nitrite-oxidizing bacteria (NOB) respond to land managements (the effect from the long-term straw incorporation and environmental variability caused by the shift from the upland stage to the paddy stage) in a rapeseed-rice rotation field remains unclear. We found the nitrite oxidation (NO) in soils increased from the upland stage to the paddy stage. An inhibitory effect of the long-term straw incorporation on NO was detectable in the upland stage. The abundance of Nitrospira was always greater than Nitrobacter, and it was affected by the rice-growing and straw incorporation while Nitrobacter was not. NO correlated positively with the abundance of Nitrospira and with soluble sulfate (SO42−), soil moisture, pH and NH4+. The high-throughput sequencing analysis of the nitrite oxidoreductase nxrA and nxrB genes for Nitrobacter- and Nitrospira-like NOB was performed respectively. The dominating (relative abundance>1%) operational taxonomic units (OTUs) from Nitrobacter were closely related to Nitrobacter hamburgensis, whereas those from Nitrospira were affiliated with or related to lineage II, lineage V and several unknown groups. Heatmap analysis showed that a few dominant Nitrobacter OTUs were affected by the straw treatment or the rice-growing, and half of the dominant Nitrospira ones were explained by at least one of the variables. Multi-response permutation procedure (MRPP) and redundancy analyses showed that the Nitrospira-like NOB community changes were significantly shaped by the land managements and the soil chemical properties, including pH, moisture and NH4+, whereas that of the Nitrobacter-like NOB community was not. These results suggested that Nitrospira are more sensitive than Nitrobacter to land management in acid and fertilized soils of a rapeseed-rice rotation field trial.