Dunaliella viridis is one of the most salt-tolerant eukaryotes and a model organism to study plant adaptation to salinity. To explore the molecular mechanisms mediating salt stress response in D. viridis, transcriptome analysis was performed by high-throughput sequencing. A total of 2242 differentially expressed genes (DEGs) were obtained, including 1563 upregulated and 679 downregulated, in plants after 6 h of salt stress (S_6h) compared with the control (Con); 394 DEGs, including 159 upregulated and 235 downregulated, in plants after 1 h of salt stress (S_1h) compared with the control; and 1379 DEGs, including 471 upregulated and 908 downregulated, in S_6h compared with S_1h. GO and KEGG analyses revealed that these DEGs were enriched in biological processes such as metabolism, genetic information transmission, signal transduction, and material transport. Further gene expression analysis and functional annotation showed that genes involved in photosynthesis were induced under salt stress. Ornithine decarboxylase and S-adenosylmethionine decarboxylase involved in polyamine synthesis and metabolism were significantly upregulated. Synthesis of molecules involved in cell cycle regulation such as G1-S phase transition protein, cyclin, and cyclin-dependent kinase was induced under salt stress. Ubiquitin, ubiquitin conjugatase, and 26S proteasome regulatory subunit were significantly different in S_6h vs._S_1h (P < 0.01). We also found that calmodulin (CaM), calcium-calmodulin dependent protein kinase (CaMK), calcium-calmodulin dependent protein kinase kinase (CaMKK), and cGMP-dependent protein kinase genes were significantly upregulated. These results indicate that calcium messenger pathway and cGMP signaling pathway play important roles in salt stress response in D. viridis. Quantitative real-time PCR (qRT-PCR) was used to validate the high-throughput sequencing, and the expression patterns of ten randomly selected genes under salt stress at different time points were further analyzed.

杜氏藻是最耐盐的真核生物之一，是研究植物对盐分适应性的模型生物。探索介导的盐衣藻盐胁迫响应的分子机制，通过高通量测序进行转录组分析。与对照（Con）相比，盐胁迫6小时（S_6h）后，植物中共获得2242个差异表达基因（DEGs），包括1563个上调和679个下调。与对照相比，盐胁迫1 h（S_1h）后植物中有394个DEG，包括159个上调和235个下调；与S_1h相比，S_6h中有1379个DEG，包括471个上调和908个下调。GO和KEGG分析表明，这些DEG富含生物过程，例如代谢，遗传信息传递，信号转导和物质运输。进一步的基因表达分析和功能注释表明，在盐胁迫下诱导了参与光合作用的基因。参与多胺合成和代谢的鸟氨酸脱羧酶和S-腺苷甲硫氨酸脱羧酶明显上调。在盐胁迫下诱导了参与细胞周期调控的分子（如G1-S相变蛋白，细胞周期蛋白和细胞周期蛋白依赖性激酶）的合成。泛素，泛素结合酶和26S蛋白酶体调节亚基在S_6h与_S_1h中有显着差异（P  <0.01）。我们还发现钙调蛋白（CaM），钙钙调蛋白依赖性蛋白激酶（CaMK），钙钙调蛋白依赖性蛋白激酶激酶（CaMKK）和cGMP依赖性蛋白激酶基因显着上调。这些结果表明，钙信使途径和cGMP信号传导途径在D. viridis的盐胁迫反应中发挥重要作用。利用实时荧光定量PCR（qRT-PCR）验证了高通量测序，并进一步分析了十个随机选择的基因在盐胁迫下不同时间点的表达模式。