Archaeal Biology Center, Synthetic Biology Research Center, Shenzhen Key Laboratory of Marine Microbiome Engineering, Key Laboratory of Marine Microbiome Engineering of Guangdong Higher Education Institutes, Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China; College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
Archaeal Biology Center, Synthetic Biology Research Center, Shenzhen Key Laboratory of Marine Microbiome Engineering, Key Laboratory of Marine Microbiome Engineering of Guangdong Higher Education Institutes, Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China.
Sci Total Environ. 2024 Nov 15;951:175677. doi: 10.1016/j.scitotenv.2024.175677. Epub 2024 Aug 22.
Although mangrove forests can uptake atmospheric CO and store carbon as organic matter called "blue carbon", it is also an important natural source of greenhouse gas methane. Methanogens are major contributors to methane and play important roles in the global carbon cycle. However, our understanding of the key microbes and metabolic pathways responsible for methanogenesis under specific substrates in mangrove sediments is still very limited. Here, we set an anaerobic incubation to evaluate the responses of methanogens in mangrove sediments from South China to the addition of diverse methanogenic substrates (H/CO, acetate, trimethylamine (TMA), and methanethiol (MT)) and further investigated the dynamics of the whole microbial community. Our results showed that diverse substrates stimulated methanogenic activities at different times. The stimulation of methanogenesis was more pronounced at early and late periods by the addition of methylotrophic substrates TMA and MT, respectively. The amplicon sequencing analysis showed that genus Methanococcoides was mainly responsible for TMA-utilized methanogenesis in mangrove sediment, while the multitrophic Methanococcus was most abundant in H/CO and MT treatments. Apart from that, the bacteria enrichments of Syntrophotalea, Clostridium_sensu_stricto_12, Fusibacter in MT treatments might also be associated with the stimulation of methane production. In addition, the metagenomic analysis suggested that Methanosarcinaceae was also one of the key methanogens in MT treatments with different genomic information compared to that in TMA treatments. Finally, the total relative abundances of methanogenesis-related genes were also highest in TMA and MT treatments. These results will help advance our understanding of the contributions of different methanogenesis pathways and methanogens to methane emissions in mangrove sediments.
尽管红树林可以吸收大气中的 CO 并将其作为有机物质（称为“蓝碳”）储存起来，但它也是温室气体甲烷的一个重要自然来源。产甲烷菌是甲烷的主要贡献者，在全球碳循环中发挥着重要作用。然而，我们对在红树林沉积物中特定基质条件下导致产甲烷作用的关键微生物和代谢途径的理解仍然非常有限。在这里，我们进行了一项厌氧培养实验，以评估来自中国南方的红树林沉积物中产甲烷菌对多种产甲烷基质（H/CO、乙酸盐、三甲胺（TMA）和甲硫醇（MT））添加的响应，并进一步研究了整个微生物群落的动态变化。我们的结果表明，不同的基质在不同的时间刺激了产甲烷作用。添加甲基营养型基质 TMA 和 MT 分别在早期和晚期更显著地刺激了甲烷生成。扩增子测序分析表明，产甲烷菌属 Methanococcoides 主要负责红树林沉积物中 TMA 利用的产甲烷作用，而 Methanococcus 则在 H/CO 和 MT 处理中最为丰富。此外，MT 处理中 Syntrophotalea、Clostridium_sensu_stricto_12、Fusibacter 的细菌富集可能也与甲烷生成的刺激有关。此外，宏基因组分析表明，与 TMA 处理相比，Methanosarcinaceae 也是 MT 处理中关键的产甲烷菌之一，其基因组信息不同。最后，产甲烷作用相关基因的总相对丰度在 TMA 和 MT 处理中也是最高的。这些结果将有助于我们更好地理解不同的产甲烷途径和产甲烷菌对红树林沉积物中甲烷排放的贡献。
