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Biogeosciences An interactive open-access journal of the European Geosciences Union
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Volume 13, issue 23
Biogeosciences, 13, 6507–6518, 2016
https://doi.org/10.5194/bg-13-6507-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 13, 6507–6518, 2016
https://doi.org/10.5194/bg-13-6507-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 13 Dec 2016

Research article | 13 Dec 2016

Transcriptional activities of methanogens and methanotrophs vary with methane emission flux in rice soils under chronic nutrient constraints of phosphorus and potassium

Rong Sheng1,3, Anlei Chen1, Miaomiao Zhang1, Andrew S. Whiteley2,3, Deepak Kumaresan2,3, and Wenxue Wei1,3 Rong Sheng et al.
  • 1Key laboratory of Agro-ecological Processes in Subtropical Regions and Taoyuan Agro-ecosystem Research Station, Soil Molecular Ecology Section, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China
  • 2School of Earth and Environment, The University of Western Australia, Perth 6009, Australia
  • 3ISA-CAS and UWA Joint Laboratory for Soil Systems Biology, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China

Abstract. Nutrient status in soil is crucial for the growth and development of plants which indirectly or directly affect the ecophysiological functions of resident soil microorganisms. Soil methanogens and methanotrophs can be affected by soil nutrient availabilities and plant growth, which in turn modulate methane (CH4) emissions. Here, we assessed whether deficits in soil-available phosphorus (P) and potassium (K) modulated the activities of methanogens and methanotrophs in a long-term (20 year) experimental system involving limitation in either one or both nutrients. Results showed that a large amount of CH4 was emitted from paddy soil at rice tillering stage (flooding) while CH4 flux was minimum at ripening stage (drying). Compared to soils amended with NPK fertiliser treatment, the soils without P input significantly reduced methane flux rates, whereas those without K input did not. Under P limitation, methanotroph transcript copy number significantly increased in tandem with a decrease in methanogen transcript abundance, suggesting that P-deficiency-induced changes in soil physio-chemical properties, in tandem with rice plant growth, might constrain the activity of methanogens, whereas the methanotrophs might be adaptive to this soil environment. In contrast, lower transcript abundance of both methanogen and methanotrophs were observed in K-deficient soils. Assessments of community structures based upon transcripts indicated that soils deficient in P induced greater shifts in the active methanotrophic community than K-deficient soils, while similar community structures of active methanogens were observed in both treatments. These results suggested that the population dynamics of methanogens and methanotrophs could vary along with the changes in plant growth states and soil properties induced by nutrient deficiency.

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Whilst previous studies have focused on the impact of nitrogen on microbe-mediated methane flux, little is known about the role of phosphorus and potassium. Here, we report that P-deficiency-induced changes in soil properties and plant growth state reduced CH4 flux from paddy soil, which was closely correlated with the abundance and community structures of active methanogens and methanotrophs. These results can benefit the effective nutrient management of paddy fields to reduce methane emission.
Whilst previous studies have focused on the impact of nitrogen on microbe-mediated methane flux,...
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