本研究以玛氏骨条藻(Skeletonema marinoi)转录组信息为基础,发现玛氏骨条藻中存在26个与细胞死亡相关的酶以及37个编码这些酶的基因。这些编码基因的序列比对结果表明,其与假微型海链藻(Thalassiosira pseudonana)和大洋海链藻(Thalassiosira oceanica)的同源基因具有较高的一致性。对这些样品进行数字基因表达谱的差异基因分析,获得了不同生长时期时与细胞死亡过程有关的编码基因的差异表达数据。结果发现,在稳定期和衰亡期,与抗氧化胁迫作用相关的关键酶(如过氧化物酶5、铜锌超氧化物歧化酶)、与RNA的加工与降解过程有关的功能基因(如多核糖核苷酸核苷转移酶、5’-3’核糖核酸外切酶2)以及细胞死亡特异蛋白的基因表达量显著高于指数期。本论文主要是通过对转录组数据进行分析得到基因转录组水平差异表达结果,为蛋白水平研究提供一种可能性变化趋势和潜在数据依据,同时为以后研究提供数据基础及研究方向。本研究也为进一步探讨硅藻的细胞死亡机制奠定了基础,也为深入理解赤潮的消亡过程提供了新的视角。
The transcriptome of Skeletonema marinoi at different growth stages was analyzed with Illumi- na-Hiseq2000 platform sequencing technology, producing and identifying 39 098 transcripts. Assembled sequences were subjected to NR BLAST similarity searches and Kyoto Encyclopedia of Genes and annota- ted with Gene Ontology (GO) and Genomes orthology (KO) identifiers. These analyses identified many important metabolic pathways and functional genes of S. marinoi, especially the functional genes related to cell death of S. rnarinoi involving 26 enzymes and 37 coding genes was analyzed and constructed on the basis of its transcriptome data. Comparative analysis of the homologous genes of S. marinoi, Thalassiosi- ra oceanica and Thalassiosira pseudonana with BLASTx method, the results showed relatively high ho- mologous genes between T. pseudonana and S. marinoi. The gene differential expression related to cell death of S. marinoi was identified at different growth stages using digital gene expression profiling. Key enzymes related to antioxidant stress (peroxiredoxin 5, superoxide dismutase, Cu-Zn family), RNA pro- cessing and degradation (polyribonucleotide nucleotidyltransferase, 5'- 3' exoribonuclease 2) and death specific protein (DSP) in stationary phase and decline phase were significantly higher compared to expo- nential growth phase. The expression of Cu-Zn-SOD gene was significantly lower in stationary phase and decline phase than in the exponential phase (stationary phase and decline phase log2 (Fold Change) was - 5.03 and -2.93; exponential phase log2 (Fold Change) was 0). The gene expression of polyribonucleotide nucleotidyltransferase was significantly higher in stationary phase and decline phase than in the exponential phase (stationary phase arid decline phase log2 (Fold Change) was 3.32 and 3.87; exponential phase log2 (Fold Change) was 0). The gene expression of DSP was significantly higher in decline phase than in the exponential phase (decline phase