Photosynthesis and genome evolution of cyanobacteria from polar environments

极地环境蓝藻的光合作用和基因组进化

• 批准号: 2891929
• 金额: --
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2891929
• 关键词: Photosynthesis; genome; evolution; cyanobacteria; polar

Cyanobacteria are the only bacteria capable of oxygenic photosynthesis. They have shaped Earth's biogeochemical cycles and biodiversity for billions of years. Cyanobacteria are cosmopolitan, but they are especially successful in extreme habitats. Particularly, in polar freshwater ecosystems where they form complex cyanobacteria-dominated microbial mat communities and are important primary producers, driving food webs and carbon cycling.However, adaptation of photosynthesis to polar habitats remains poorly understood. In these habitats, low temperatures are often accompanied by extreme fluctuations in irradiance. High light intensities and ultraviolet radiation are common for shallow meltwater ponds on the ice shelves. In contrast, only a tiny fraction of the surface irradiance is transmitted through the ice at the bottom of perennially ice-covered lakes. This suggests that cyanobacteria have a tremendous capacity to acclimate photosynthesis to challenging conditions. The fundamental principles that govern such adaptations can provide insights not only into engineering more robust or resilient strains for biotech applications, translatable toeukaryotic algae and crops, but also on the biological plasticity that enables the endurance of oxygenic photosynthesis over the long history of our constantly changing planet.The aim of the project is to characterize in real time, at a physiological and genomic level, how photosynthesis in cyanobacteria acclimates to harsh environmental conditions using adaptive laboratory evolution experiments.The student will grow Antarctic cyanobacteria in the laboratory to evaluate their fitness and photosynthetic performance under extreme light conditions such as very low or high intensities, different UV radiation levels, and in combination with changes in temperature. Selected populations of Antarctic strains will be gradually acclimated to benign laboratory conditions as to release selective pressures over a period of time. In parallel, laboratorycyanobacteria will be gradually acclimated to harsh polar-like conditions and their fitness compared to Antarctic isolates. Genomes will be sequenced, and genetic changes will be correlated with photosynthetic performance.The NHM also has collections of over 10,000 historic samples of cyanobacteria, including those collected during Captain Scott's British Antarctic Expedition over a century ago that will be sequenced using ancient DNA extraction approaches and compared with cyanobacteria isolates and available metagenome data from Antarctica.

蓝细菌是唯一能够进行氧合光合作用的细菌。他们塑造了地球的生物地球化学周期和生物多样性数十亿年。蓝细菌是国际化的，但在极端栖息地中特别成功。特别是，在极地淡水生态系统中，它们形成了复杂的蓝细菌主导的微生物垫群落，并且是重要的主要生产者，驾驶食物网和碳循环。在这些栖息地中，低温通常伴随着辐照度的极端波动。高光强度和紫外线辐射对于冰架上的浅水池很常见。相比之下，只有一小部分表面辐照度通过冰底部的冰层传播。这表明蓝细菌具有使光合作用的巨大能力适应具有挑战性的条件。控制这种适应的基本原理不仅可以为工程提供更强大或更弹性的菌株，用于生物技术应用，可翻译的to核藻类和农作物，而且还可以对生物可塑性，从而使氧气的光合物的耐力在我们不断变化的层次上的较长层次的范围内，可以在我们的持续变化的范围内。使用适应性实验室进化实验适应蓝细菌的光合作用可适应恶劣的环境条件。学生将在实验室中生长南极蓝细菌，以评估其在非常低或高强度的极端光条件下的适应性和光合作用，例如非常低或高的强度，不同的UV辐射水平以及与温度变化的结合。选定的南极菌株种群将逐渐适应良性实验室条件，以释放一段时间内选择性压力。同时，与南极分离株相比，实验室循环细菌将逐渐适应严格的极性状况及其适应性。基因组将进行测序，遗传变化将与光合作用的性能相关。NHM还拥有10,000多种历史性的蓝细菌样本，其中包括一个世纪前斯科特·斯科特（Scott Scott）英国南极探险期间收集的那些，它将使用古老的DNA萃取方法对其进行测序，并与cyanobacteria extalica进行了序列和可用的元素。