Non-linear Physiology and Gene Expression Responses of Harmful Alga Heterosigma akashiwo to Rising CO2
Non-linear Physiology and Gene Expression Responses of Harmful Alga Heterosigma akashiwo to Rising CO2
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DOI：
10.1016/j.protis.2018.10.002
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发表时间：
2019-02-01
期刊：
影响因子：
2.5
通讯作者：
Dyhrman, Sonya T.
中科院分区：
文献类型：
--
作者：
Hennon, Gwenn M. M.;Williamson, Olivia M.;Dyhrman, Sonya T.
赤潮异弯藻是一种以形成鱼毒水华而闻名的针芽植物。为了预测CO2浓度升高对H. akashiwo，有必要了解在CO2浓度范围内影响生长率的因素。在这里，我们研究了H.从200到1000 ppm CO2的浓度。生长速率数据结合从这个和以前的研究，并适合与CO2限制抑制模型，揭示了一个明显的增长最佳约600-800 ppm的CO2。生理变化包括在类似于800 ppm CO2时C：N比的显著增加和在类似于1000 ppm时过氧化氢浓度的显著降低。H. akashiwo揭示了在类似于600和类似于800 ppm CO2之间代谢途径基因表达的明显差异。通过共表达的层次聚类确定了与CO2和生长速率显著相关的基因组。与CO2显著差异表达的基因包括碳浓缩机制基因，如β-碳酸酐酶和碳酸氢盐转运蛋白，这可能是生理变化的基础。参与细胞运动的基因被升高的CO2和生长速率显著改变，这表明未来的海洋条件可能会改变该物种的游泳行为。(C)2018 Elsevier GmbH. All rights reserved.
Heterosigma akashiwo is a raphidophyte known for forming ichthyotoxic blooms. In order to predict the potential impacts of rising CO2 on H. akashiwo it is necessary to understand the factors influencing growth rates over a range of CO2 concentrations. Here we examined the physiology and gene expression response of H. akashiwo to concentrations from 200 to 1000 ppm CO2. Growth rate data were combined from this and previous studies and fit with a CO2 limitation-inhibition model that revealed an apparent growth optimum around 600-800 ppm CO2. Physiological changes included a significant increase in C:N ratio at similar to 800 ppm CO2 and a significant decrease in hydrogen peroxide concentration at similar to 1000 ppm. Whole transcriptome sequencing of H. akashiwo revealed sharp distinctions in metabolic pathway gene expression between similar to 600 and similar to 800 ppm CO2. Hierarchical clustering by co-expression identified groups of genes with significant correlations to CO2 and growth rate. Genes with significant differential expression with CO2 included carbon concentrating mechanism genes such as beta-carbonic anhydrases and a bicarbonate transporter, which may underpin shifts in physiology. Genes involved in cell motility were significantly changed by both elevated CO2 and growth rate, suggesting that future ocean conditions could modify swimming behavior in this species. (C) 2018 Elsevier GmbH. All rights reserved.