An integrated ecophysiology and omics study of phosphorus limitation in methane-oxidising bacteria (EcoMethane)

甲烷是一种强效的大气温室气体，其浓度在过去十年中持续增加，导致最近在格拉斯哥举行的第26届联合国气候变化大会上，全球努力到2030年将甲烷排放量减少30%。甲烷氧化细菌（甲烷氧化菌）利用甲烷作为碳和能源，帮助减少了高达90%的甲烷排放。因此，甲烷氧化菌在全球甲烷循环中发挥着至关重要的作用，任何对自然环境中甲烷氧化菌活动的干扰，无论是生物的还是非生物的，都将对我们到2030年将全球变暖限制在1.5摄氏度的能力产生重大影响。然而，在现实世界中，人们对甲烷化菌的活性是如何调节的知之甚少，特别是磷(P)等关键营养物质的调节，磷是一种在许多生态系统中限制植物和微生物生长的限制性营养物质。我以trichosporium Methylosinus OB3b为模型，证明了甲烷化菌可以通过用替代的非P代糖脂替代膜磷脂来减少其细胞P配额，以应对P限制。参与这种所谓的脂质重塑途径的基因在所有的甲烷氧化菌中都是严格保守的，这表明脂质重塑是甲烷氧化菌的一个保守特征。然而，这种适应磷限制的生态和生理后果尚不清楚。这一点很重要，因为它可能对甲烷氧化菌的活性和死亡率（甲烷氧化菌与原生食草动物和噬菌体的生物相互作用）产生重要影响，从而影响全球甲烷收支。在这里，我的目标是使用综合组学方法来揭示甲烷氧化菌的生理生态，以及它们对模型甲烷氧化菌和自然栖息地中磷限制的反应。该项目的成果将填补我们对自然环境中甲烷氧化菌活动的理解的重大知识空白

Methane is a potent atmospheric greenhouse gas with concentrations continuing to increase in the past decade,leading to a recent global effort at COP26 in Glasgow to reduce methane emissions by 30% by 2030. Methane-oxidising bacteria (methanotrophs) use methane as a carbon and energy source, helping to mitigate as much as 90%of methane emissions. As such, methanotrophs play a vital role in the global methane cycle and any disturbance,biotic or abiotic, of methanotroph activity in the natural environment would exert significant impacts on our abilityto limit global warming by 1.5 degrees celsius by 2030. However, very little is known about how methanotroph activity isregulated in the real world, particularly by key nutrients like phosphorus (P), a limiting nutrient constraining plantand microbial growth in many ecosystems. Using Methylosinus trichosporium OB3b as the model, I havedemonstrated that methanotrophs can reduce their cellular P quota in response to P limitation by substitutingmembrane phospholipids with alternative non-P surrogate glycolipids. The genes involved in this so-called lipidremodelling pathway are strictly conserved in all proteobacterial methanotrophs, suggesting that lipid remodellingis a conserved trait in methanotrophs. However, the ecological and physiological consequences of such anadaptation to P limitation are unknown. This is important because it may have important consequences formethanotroph activity and mortality (biotic interactions of methanotrophs with protist grazers and bacteriophages),thus affecting the global methane budget. Here, I aim to use an integrated omics approach to uncover theecophysiology of methanotrophs and their response to P limitation in both model methanotrophs and in their naturalhabitat. The outcomes of this project will fill a major knowledge gap in our understanding of methanotroph activityin the natural environment