基于玛氏骨条藻转录组的脂肪酸合成途径分析

Description of Fatty Acid Synthesis Pathway Based on Skeletonema marinoi Transcriptome

本研究利用Illumina Hiseq2000对不同生长时期的玛氏骨条藻(Skeletonema marinoi)进行转录组测序,得到的转录本通过NR、NT、Swiss-Prot和KOG数据库进行功能分类,通过GO和KEGG数据库进行相关代谢途径分析和基因差异表达分析,在此基础上构建了S.marinoi的脂肪酸生物合成途径,发现共存在26种酶和蛋白对应的33个编码基因,对这33个基因序列进行比对发现其与假微型海链藻(Thalassiosira pseudonana)的同源性较高。在该代谢通路中,S.marinoi在不同生长时期出现显著差异表达的基因有15个。与指数期相比,柠檬酸裂解酶和长链酰基-CoA合成酶(Comp14198_c0)的编码基因在稳定期和衰亡期出现显著下调表达,而柠檬酸合酶的编码基因仅在稳定期出现显著下调表达。与之相反的是,以乙酰-CoA羧化酶编码基因为代表的12个编码基因在稳定期和衰亡期均出现了显著上调。通过分析,初步推测S.marinoi在稳定期的脂肪酸合成能力高于指数期。这些信息为海洋微藻脂肪酸生物合成途径的研究提供了理论基础,有助于对S.marinoi进行基因改造,提高脂肪酸的合成量。同时,又能为赤潮的防治提供新的思路。

The transcriptome of Skeletonema marinoi at different growth stages was analyzed with Illumina Hiseq2000 platform sequencing technology.we aligned all the transcripts with NR database,NT database,Swiss-Prot database and KOG database to annotate the function.By aligning GO database and KEGG database,we assigned the transcript with metabolic and different gene expression in the pathways.These analyses identified the important metabolic pathways and genes of S.marinoi,especially the fatty acid synthesis pathway involving 26 enzymes and 33 coding genes.Comparing with the homologous genes of Thalassiosira pseudonana,these genes showed little divergence.The results indicated that the number of differential expression genes was 15 in fatty acid synthesis and regulation pathway.Compared to exponential growth phase,two genes coding(ATP-citrate lyase(ACL)and long-chain acyl-CoA synthetase(LACS))showed significantly decreasing in stationary phase and decline phase,while Citrate synthase(CS)coding gene only showed significantly decreasing in stationary phase.In contrast,twelve genes coding showed significantly increasing in stationary phase and decline phase.The results indicated that the ability of fatty acid in stationary phase(SP)showed significantly increasing than exponential growth phase(EP).Our study will contribute to the genetic manipulation of Skeletonema marinoi and increase the synthesis of fatty acids.This information provides a theoretical basis for fatty acid biosynthetic pathway in marine microalgae,which contributes to genetic modification of S.marinoi to improve the content of fatty acids.At the same time,it provides a new idea for the prevention and treatment of harmful algal blooms.