Diatoms are major players in the global carbon cycle, and their metabolism is affected by ocean conditions. Understanding the impact of changing inorganic nutrients in the oceans on diatoms is crucial, given the changes in global carbon dioxide levels. Here, we present a genome-scale metabolic model ( i MK1961) for Cylindrotheca closterium , an in silico resource to understand uncharacterized metabolic functions in this ubiquitous diatom. i MK1961 represents the largest diatom metabolic model to date, comprising 1961 open reading frames and 6718 reactions. With i MK1961, we identified the metabolic response signature to cope with drastic changes in growth conditions. Comparing model predictions with Tara Oceans transcriptomics data unraveled C. closterium ’s metabolism in situ. Unexpectedly, the diatom only grows photoautotrophically in 21% of the sunlit ocean samples, while the majority of the samples indicate a mixotrophic (71%) or, in some cases, even a heterotrophic (8%) lifestyle in the light. Our findings highlight C. closterium’ s metabolic flexibility and its potential role in global carbon cycling.

中文翻译：

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普遍存在的海洋硅藻的混合营养生长


硅藻是全球碳循环的主要参与者，它们的新陈代谢受到海洋条件的影响。考虑到全球二氧化碳水平的变化，了解海洋中无机营养物质变化对硅藻的影响至关重要。在这里，我们提出了一个基因组规模的代谢模型（我MK1961）用于新月柱藻，一种计算机资源，用于了解这种普遍存在的硅藻中未表征的代谢功能。我MK1961代表了迄今为止最大的硅藻代谢模型，包括1961个开放阅读框和6718个反应。和我MK1961，我们确定了代谢反应特征，以应对生长条件的剧烈变化。比较模型预测塔拉海洋转录组学数据揭晓新月 C.的原位代谢。出乎意料的是，硅藻仅在 21% 的阳光照射海洋样本中以光合自养方式生长，而大多数样本在光照下表现出混合营养（71%），甚至在某些情况下，甚至异养（8%）生活方式。我们的研究结果强调C. 新月'代谢灵活性及其在全球碳循环中的潜在作用。