Iron storage capacities and associated ferritin gene expression among marine diatoms
Iron storage capacities and associated ferritin gene expression among marine diatoms
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DOI：
10.1002/lno.10800
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发表时间：
2018-07-01
影响因子：
4.5
通讯作者：
Marchetti, Adrian
中科院分区：
文献类型：
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作者：
Cohen, Natalie R.;Mann, Elizabeth;Marchetti, Adrian
在海洋的大片区域，铁的低可获得性调节了硅藻的生长和物种组成。硅藻物种对富铁的生理反应往往不同，在海洋含铁有限的区域添加天然和人工铁导致大型硅藻大量繁殖，主要是羽状硅藻。羽状硅藻在脉冲加铁后增殖的能力部分归因于它们获取和储存细胞内多余铁的能力，并将其储存在铁储存蛋白铁蛋白中。最近对硅藻的转录组测序表明，一些中心硅藻也含有铁蛋白。利用生理学和分子生物学相结合的技术，我们研究了在高铁浓度和低铁浓度下生长的不同系统发育的中心型和羽状型硅藻的铁储存能力和相关的铁蛋白基因表达。含铁蛋白和不含铁蛋白的硅藻在储存超过支持最大生长速度所需铁的能力方面没有系统性差异。然而，一个例外是含有铁蛋白的羽状硅藻伪硝化硅藻类，原产于东北太平洋铁有限的水域。该物种表现出极大的豪华铁储存容量，并在高铁浓度下增加铁蛋白基因表达，支持长期铁储存的作用。相比之下，另外两种表现出最低铁存储能力的硅藻包含两个不同的铁蛋白基因，其中一个铁蛋白基因在铁限制下表达增加，而第二个基因没有随着细胞铁状态的变化而变化。我们得出结论，铁蛋白可能具有多种功能，而不受硅藻系统发育的影响。
In large regions of the ocean, low iron availability regulates diatom growth and species composition. Diatom species often vary in their physiological response to iron enrichment, with natural and artificial iron additions in iron-limited regions of the ocean resulting in large blooms of primarily pennate diatoms. The ability of pennate diatoms to proliferate following pulse iron additions has been partly attributed to their ability to acquire and store excess intracellular iron in the iron storage protein ferritin. Recent transcriptome sequencing of diatoms indicate that some centric diatoms also possess ferritin. Using a combination of physiological and molecular techniques, we examined the iron storage capacities and associated ferritin gene expression in phylogenetically diverse centric and pennate diatoms grown under high and low iron concentrations. There were no systematic differences among ferritin-containing and non-containing diatom lineages in their ability to store iron in excess of that needed to support maximum growth rates. An exception, however, was the ferritin-containing pennate diatom Pseudo-nitzschia granii, native to iron-limited waters of the Northeast Pacific Ocean. This species exhibited an exceptionally large luxury iron storage capacity and increased ferritin gene expression at high iron concentrations, supporting a role in long-term iron storage. By contrast, two other diatoms species that exhibited minimal iron storage capacities contained two distinct ferritin genes where one ferritin gene increased in expression under iron limitation while the second showed no variation with cellular iron status. We conclude that ferritin may serve multiple functional roles that are independent of diatom phylogeny.