The haptophyte Phaeocystis antarctica is endemic to the Southern Ocean, where iron supply is sporadic and its availability limits primary production. In iron fertilization experiments, P. antarctica showed a prompt and steady increase in cell abundance compared to heavily silicified diatoms along with enhanced colony formation. Here we utilized a transcriptomic approach to investigate molecular responses to alleviation of iron limitation in P. antarctica. We analyzed the transcriptomic response before and after (14 h, 24 h and 72 h) iron addition to a low‐iron acclimated culture. After iron addition, we observed indicators of a quick reorganization of cellular energetics, from carbohydrate catabolism and mitochondrial energy production to anabolism. In addition to typical substitution responses from an iron‐economic toward an iron‐sufficient state for flavodoxin (ferredoxin) and plastocyanin (cytochrome c₆), we found other genes utilizing the same strategy involved in nitrogen assimilation and fatty acid desaturation. Our results shed light on a number of adaptive mechanisms that P. antarctica uses under low iron, including the utilization of a Cu‐dependent ferric reductase system and indication of mixotrophic growth. The gene expression patterns underpin P. antarctica as a quick responder to iron addition.

中文翻译：

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南极菲氏囊的转录组对铁条件变化的适应和适应的破译模式1。

附生植物南极囊藻是南洋特有的，那里的铁供应很少，其可利用性限制了初级生产。在铁肥实验中，与严重硅化的硅藻相比，南极疟原虫的细胞丰度迅速而稳定地增加，并且菌落形成增强。在这里，我们利用转录组学方法来研究减轻南极体育中铁限制的分子反应。。我们分析了添加铁至低铁适应性培养前后（14 h，24 h和72 h）的转录组反应。加入铁后，我们观察到了从碳水化合物分解代谢和线粒体能量产生到合成代谢的细胞能量快速重组的指标。除了铁经济体对黄酮毒素（铁氧还蛋白）和质体蓝素（细胞色素c ₆）的典型替代反应外，我们还发现了其他利用相同策略参与氮同化和脂肪酸去饱和的基因。我们的结果揭示了南极假单胞菌的许多适应性机制在低铁下使用，包括利用依赖铜的铁还原酶系统和混合营养生长的迹象。基因表达模式支持南极疟原虫对铁的快速反应。