Contrasting modes of inorganic carbon acquisition amongst Symbiodinium (Dinophyceae) phylotypes
Contrasting modes of inorganic carbon acquisition amongst Symbiodinium (Dinophyceae) phylotypes
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DOI：
10.1111/nph.12379
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发表时间：
2013-10-01
期刊：
影响因子：
9.4
通讯作者：
Suggett, David J.
中科院分区：
文献类型：
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作者：
Brading, Patrick;Warner, Mark E.;Suggett, David J.
对海洋酸化的日益关注突出表明，需要严格了解海洋微藻中无机碳的获取和利用。在这里，我们第一次对比了两种遗传上不同的甲藻物种共生藻属（A13和A20型），生活在共生与珊瑚礁形成corals.Both共生型在相同的环境条件下生长在连续的文化之间的这些特征。采用定量蛋白质印迹法测定Rubisco，放射性同位素C-14摄取用于表征光和总二氧化碳（TCO 2）依赖的碳固定，以及无机碳物种偏好和外部碳酸酐酶活性。A13和A20表现出相似的碳固定速率，尽管A13中Rubisco的细胞浓度大约高出4倍。CO2的吸收超过HCO 3-被发现支持大多数的碳固定在两种植物类型。然而，A20也能够间接利用HCO 3-，首先通过外部碳酸酐酶将其转化为CO2。这些结果表明，共生藻属内无机碳获取的适应性差异已经进化，因此，这对这个功能关键属如何应对海洋酸化具有根本意义。但也可能是一个关键的性状因素，影响他们的生产力时，在他们的珊瑚宿主的hospite。
Growing concerns over ocean acidification have highlighted the need to critically understand inorganic carbon acquisition and utilization in marine microalgae. Here, we contrast these characteristics for the first time between two genetically distinct dinoflagellate species of the genus Symbiodinium (phylotypes A13 and A20) that live in symbiosis with reef-forming corals.Both phylotypes were grown in continuous cultures under identical environmental conditions. Rubisco was measured using quantitative Western blots, and radioisotopic C-14 uptake was used to characterize light- and total carbon dioxide (TCO2)-dependent carbon fixation, as well as inorganic carbon species preference and external carbonic anhydrase activity.A13 and A20 exhibited similar rates of carbon fixation despite cellular concentrations of Rubisco being approximately four-fold greater in A13. The uptake of CO2 over HCO3- was found to support the majority of carbon fixation in both phylotypes. However, A20 was also able to indirectly utilize HCO3- by first converting it to CO2 via external carbonic anhydrase.These results show that adaptive differences in inorganic carbon acquisition have evolved within the Symbiodinium genus, which thus carries fundamental implications as to how this functionally key genus will respond to ocean acidification, but could also represent a key trait factor that influences their productivity when in hospite of their coral hosts.