Zhang Shaohua, Yan Lei, Cao Jiahui, Wang Kexin, Luo Ying, Hu Haiyang, Wang Lixin, Yu Ruihong, Pan Baozhu, Yu Ke, Zhao Ji, Bao Zhihua
Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau & Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China.
Inner Mongolia Key Laboratory of Environmental Pollution Control & Waste Resource Reuse, Inner Mongolia University, Hohhot, China.
Front Microbiol. 2023 Jan 6;13:1067017. doi: 10.3389/fmicb.2022.1067017. eCollection 2022.
Methanotrophs oxidize methane (CH) and greatly help in mitigating greenhouse effect. Increased temperatures due to global climate change can facilitate lake salinization, particularly in the regions with cold semiarid climate. However, the effects of salinity on the CH oxidation activity and diversity and composition of methanotrophic community in the sediment of natural lakes at a regional scale are still unclear. Therefore, we collected lake sediment samples from 13 sites in Mongolian Plateau; CH oxidation activities of methanotrophs were investigated, and the diversity and abundance of methanotrophs were analyzed using real-time quantitative polymerase chain reaction and high throughput sequencing approach. The results revealed that the diversity of methanotrophic community decreased with increasing salinity, and community structure of methanotrophs was clearly different between the hypersaline sediment samples (HRS; salinity > 0.69%) and hyposaline sediment samples (HOS; salinity < 0.69%). Types II and I methanotrophs were predominant in HRS and HOS, respectively. Salinity was significantly positively correlated with the relative abundance of and negatively correlated with that of . In addition, CH oxidation rate and gene abundance decreased with increasing salinity, and salinity directly and indirectly affected CH oxidation rate regulating the community diversity. Moreover, high salinity decreased cooperative association among methanotrophs and number of key methanotrophic species ( and , e.g). These results suggested that salinity is a major driver of CH oxidation in lake sediments and acts by regulating the diversity of methanotrophic community and accociation among the methanotrophic species.
甲烷氧化菌可氧化甲烷（CH），对缓解温室效应有很大帮助。全球气候变化导致的气温升高会促进湖泊盐碱化，尤其是在寒冷半干旱气候地区。然而，在区域尺度上，盐度对天然湖泊沉积物中甲烷氧化活性、甲烷氧化菌群落多样性和组成的影响仍不明确。因此，我们从蒙古高原的13个地点采集了湖泊沉积物样本；研究了甲烷氧化菌的甲烷氧化活性，并采用实时定量聚合酶链反应和高通量测序方法分析了甲烷氧化菌的多样性和丰度。结果表明，甲烷氧化菌群落的多样性随着盐度的增加而降低，高盐沉积物样本（HRS；盐度>0.69%）和低盐沉积物样本（HOS；盐度<0.69%）之间甲烷氧化菌的群落结构明显不同。II型和I型甲烷氧化菌分别在HRS和HOS中占主导地位。盐度与 的相对丰度显著正相关，与 的相对丰度显著负相关。此外，甲烷氧化速率和 基因丰度随着盐度的增加而降低，盐度通过调节群落多样性直接和间接影响甲烷氧化速率。此外，高盐度降低了甲烷氧化菌之间的协同关联以及关键甲烷氧化菌种（如 和 ）的数量。这些结果表明，盐度是湖泊沉积物中甲烷氧化的主要驱动因素，通过调节甲烷氧化菌群落的多样性和甲烷氧化菌种之间的关联来发挥作用。
