Investigating the environmental relevance of methoxydotrophic archaea

研究甲氧营养古菌的环境相关性

• 批准号: 532554430
• 负责人: Dr. Julia Kurth
• 金额: --
• 依托单位: Department of Biology
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/532554430?language=en
• 关键词: Investigating; environmental; relevance; methoxydotrophic; archaea

Methoxylated aromatic compounds are key components of lignin and coal and are very abundant on Earth. Therefore, it is surprising that conversion of these compounds has previously only been described for bacteria and not for archaea, although the latter have been important drivers of various biogeochemical cycles for billions of years. In 2016, however, it was discovered that the methane-producing archaeon Methermicoccus shengliensis can grow on methoxylated compounds. Methane-producing archaea, so-called methanogens, are major players in the global carbon cycle as well as main producers of the greenhouse gas methane. Therefore, it is crucial to investigate those organisms and to reveal deeper insights into their metabolisms. Using a complementary array of physiological and -omics methods, we showed that M. shengliensis uses a bacteria-like methyl transfer (Mto) system for methanogenesis with methoxylated compounds as substrates and revealed differences in the carbon and energy metabolism compared to the classic pathway using methylated compounds. The discovery of the mto genes enabled us to search for further archaea with the genetic potential to convert methoxylated aromatic compounds. For one of these archaea, the non-methanogenic archaeon Archaeoglobus fulgidus, we could show that this archaeon indeed can grow on methoxylated compounds. Additionally, other archaea such as the hydrogen-utilizing methanogen Methanothermobacter tenebrarum and uncultured archaea such as Verstraetearchaeota appear to have the genetic potential for growth on methoxylated compounds. These findings together with the abundance of methoxylated compounds in natural environments suggest that methoxydotrophic archaea might play an underestimated but vital role for the global carbon cycle. In the proposed project, I intend to investigate the environmental role of methoxydotrophic archaea. We will perform high-throughput sequencing targeting diagnostic genes to survey their distribution and abundance patterns in various habitats such as hydrothermal vents, oil reservoirs or deadwood. Samples with high abundance of methoxydotrophic archaea will be used for enrichment cultures in bottles and in bioreactors to obtain novel isolates. These cultures will further be used to study the ecophysiology of methoxydotrophic archaea, bacteria and potentially fungi present in the cultures by performing RT-qPCR and fluorescence in situ hybridization (FISH) targeting DNA/RNA sequences of genes involved in methoxydotrophic growth as well as metatranscriptomics. Furthermore, novel isolates of methoxydotrophic archaea will be physiologically characterized. This project will provide insights into the methoxydotrophic capabilities of diverse archaea, their exceptional metabolisms alongside with a greater understanding of the role of these archaea in the environment.

甲氧基芳香族化合物是木质素和煤的关键成分，在地球上非常丰富。因此，令人惊讶的是，这些化合物的转化以前只被描述为细菌而不是古细菌，尽管后者在数十亿年来一直是各种生物地球化学循环的重要驱动力。然而，在2016年，人们发现产甲烷的古细菌生力热微球菌（Methermicoccus shengliensis）可以在甲氧基化合物上生长。产生甲烷的古细菌，即所谓的产甲烷菌，是全球碳循环的主要参与者，也是温室气体甲烷的主要生产者。因此，研究这些生物并深入了解它们的代谢是至关重要的。利用一系列互补的生理学和组学方法，我们发现m.s shengliensis使用一种类似细菌的甲基转移（Mto）系统以甲氧基化化合物为底物进行甲烷生成，并揭示了与使用甲基化化合物的经典途径相比，碳和能量代谢的差异。mto基因的发现使我们能够进一步寻找具有转化甲氧基化芳香化合物的遗传潜力的古细菌。对于其中一种古细菌，不产甲烷的古细菌，我们可以证明这种古细菌确实可以在甲氧基化的化合物上生长。此外，其他古细菌，如利用氢的产甲烷菌（Methanothermobacter tenebrarum）和未培养的古细菌（如Verstraetearchaeota）似乎具有在甲氧基化化合物上生长的遗传潜力。这些发现与自然环境中丰富的甲氧基化化合物一起表明，甲氧营养古细菌可能在全球碳循环中发挥着被低估但至关重要的作用。在本项目中，我打算研究甲氧营养古菌的环境作用。我们将对诊断基因进行高通量测序，以调查其在热液喷口、油藏或枯木等不同栖息地的分布和丰度模式。具有高丰度甲氧营养古菌的样品将用于瓶中和生物反应器中的富集培养，以获得新的分离株。这些培养物将通过RT-qPCR和荧光原位杂交（FISH）针对参与甲氧营养生长的基因的DNA/RNA序列以及亚转录组学，进一步用于研究培养物中存在的甲氧营养古菌、细菌和潜在真菌的生态生理。此外，新分离的甲氧营养古细菌将被生理表征。该项目将深入了解各种古菌的甲氧营养能力，它们的特殊代谢以及对这些古菌在环境中的作用的更深入了解。