Transcriptional Response of Osmolyte Synthetic Pathways and Membrane Transporters in a Euryhaline Diatom During Long‐term Acclimation to a Salinity Gradient
Transcriptional Response of Osmolyte Synthetic Pathways and Membrane Transporters in a Euryhaline Diatom During Long‐term Acclimation to a Salinity Gradient
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DOI：
10.1111/jpy.13061
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发表时间：
2020-08
影响因子：
2.9
通讯作者：
Teofil Nakov;Kathryn J. Judy;K. Downey;Elizabeth C. Ruck;Andrew J. Alverson
中科院分区：
文献类型：
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作者：
Teofil Nakov;Kathryn J. Judy;K. Downey;Elizabeth C. Ruck;Andrew J. Alverson
从生态学和应用的角度来看，硅藻如何对渗透压的波动做出反应都是重要的。众所周知，渗透胁迫会影响光合作用，并会导致制药和替代燃料行业所需化合物的积累。对渗透胁迫的基因表达反应已经在短期试验中进行了研究，但尚不清楚在长期驯化过程中是否采用了同样的机制。我们使用RNA-seq研究了在长期适应了从淡水到海水的自然范围的盐度之后，泛盐生硅藻隐环藻的全基因组转录模式。长期驯化的隐翅虫表现出对甘氨酸甜菜碱、牛磺酸和二甲基磺酸丙酸酯(DMSP)渗透调节物质的诱导合成或抑制降解。虽然Pro浓度的变化是短期渗透胁迫的主要反应之一，但在我们的长期实验中，我们没有检测到Pro生物合成途径的转录变化。膜转运蛋白的表达显示出钾的输入和钠的输出增加的总体趋势，这与电化学梯度和对共转运分子的依赖相一致。我们的结果表明，不同的基因型在生长和基因表达反应指标上存在显著差异，并表明在短期渗透胁迫中起重要作用的Pro合成的调节在长期驯化中可能无法维持。使用时间进程基因表达实验、新陈代谢组学和基因功能的遗传验证的进一步检查将加强从RNA-SEQ数据推断的模式。
How diatoms respond to fluctuations in osmotic pressure is important from both ecological and applied perspectives. It is well known that osmotic stress affects photosynthesis and can result in the accumulation of compounds desirable in pharmaceutical and alternative fuel industries. Gene expression responses to osmotic stress have been studied in short‐term trials, but it is unclear whether the same mechanisms are recruited during long‐term acclimation. We used RNA‐seq to study the genome‐wide transcription patterns in the euryhaline diatom, Cyclotella cryptica, following long‐term acclimation to salinity that spanned the natural range of fresh to oceanic water. Long‐term acclimated C. cryptica exhibited induced synthesis or repressed degradation of the osmolytes glycine betaine, taurine and dimethylsulfoniopropionate (DMSP). Although changes in proline concentration is one of the main responses in short‐term osmotic stress, we did not detect a transcriptional change in proline biosynthetic pathways in our long‐term experiment. Expression of membrane transporters showed a general tendency for increased import of potassium and export of sodium, consistent with the electrochemical gradients and dependence on co‐transported molecules. Our results show substantial between‐genotype differences in growth and gene expression reaction norms and suggest that the regulation of proline synthesis important in short‐term osmotic stress might not be maintained in long‐term acclimation. Further examination using time‐course gene expression experiments, metabolomics and genetic validation of gene functions would reinforce patterns inferred from RNA‐seq data.