Divergent responses of methanogenic archaeal communities in two rice cultivars to elevated ground-level O-3

摘要

Inhibitive effect of elevated ground-level ozone (O-3) on paddy methane (CH4) emission varies with rice cultivars. However, little information is available on its microbial mechanism. For this purpose, the responses of methane-metabolizing microorganisms, methanogenic archaea and methanotrophic bacteria to O-3 pollution were investigated in the O-3-tolerant (YD6) and the O-3-sensitive (IIY084) cultivars at two rice growth stages in Free Air Concentration Elevation of O-3 (O-3-FACE) system of China. It was found that O-3 pollution didn't change the abundances of Type I and Type II methanotrophic bacteria at two rice stages. For methanogenic archaea, their abundances in both cultivars were decreased by O-3 pollution at the tillering stage. Furthermore, a greater negative influence on methanogenic archaeal community was observed on IIY084 than on YD6: at tittering stage, the alpha diversity indices of methanogenic archaeal community in IIY084 was decreased to a greater extent than in YD6; IIY084 shifted methanogenic archaeal community composition and decreased the abundances and the diversities of Methanosarcinaceae and Methanosaetaceae as well as the abundance of Methanomicrobiales, while the diversity of Methanocellaceae were increased in YD6. These findings indicate that the variations in the responses of paddy CH4 emission to O-3 pollution between cultivars could result from the divergent responses of their methanogenic archaea. (C) 2016 Elsevier Ltd. All rights reserved.