休哈塔假丝酵母转化木糖和葡萄糖为乙醇的发酵转录谱

Transcript profile of converting xylose and glucose to ethanol by Candida shehatae

摘要:

摘要:【目的】探究木糖发酵典型菌株休哈塔假丝酵母在己糖和戊糖发酵中的转录谱及差异，筛选出与木糖利用和乙醇发酵代谢途径及调控相关的关键性酶和功能蛋白质基因。【方法】应用新一代高通量测序技术454 GS FLX Titanium分别构建了休哈塔假丝酵母木糖、葡萄糖发酵的cDNA 文库，并进行De novo转录组的表达序列标签大规模测序和序列比较分析，进而挖掘出该酵母中参与木糖代谢和乙醇发酵的相关基因。【结果】分别对木糖和葡萄糖发酵样本进行二分之一RUN 测序并各自得到60万条reads，序列平均长度 400 bp。共拼接得到7250条(木糖)和7168条(葡萄糖) contigs，并利用BLAST对木糖样品和葡萄糖样品中的2421个基因(contig)和2456个基因(contig)进行了功能注释和GO分类。通过两个文库间的序列对比分析，共发现158个基因属于差异表达状态(P＜0.05)。基于经典的糖酵解及乙醇发酵途径筛选出与木糖乙醇发酵相关的候选基因，并且比较分析其转录水平的差异。【结论】基于大规模转录谱测序和比较分析首次筛选出休哈塔假丝酵母中参与木糖代谢和乙醇发酵的基因群，可为后续的分子生物学及代谢调控研究提供基础数据。

关键词:关键词:休哈塔假丝酵母，木糖代谢，乙醇发酵，转录谱，表达序列标签

Abstract:

Abstract:［Objective］We detected and analyzed transcript profile differences between hexose and pentose fermentation by Candida shehatae，a typical xylose fermenting yeast strain． On this basis，the encoding genes of key enzymes and functional protein were screened for discovering candidates of metabolism and regulation．［Methods］To discover the key genes of xylose metabolism and ethanol fermentation in Candida shehatae，we performed a new high throughout de novo transcriptome sequencing technology on Roche 454 GS FLX Titanium platform． Two cDNA libraries were constructed and sequenced for xylose and glucose fermentation for comparison of its expressed sequence tags differences． ［Results］Second sequencing run resulted in 600000 reads with the average length of 400bp for each cDNA library．We got 7250 and 7168 contigs by assembly，and annotated 2412 and 2456 unique genes by BLAST and Gene Ontology analysis for xylose and glucose respectively． By comparison，we identified 158 genes as different expression genes candidates at p＜0.05 for xylose metabolism and ethanol fermentation in Candida shehatae．［Conclusions］The group genes for xylose metabolism and ethanol fermentation in Candida shehatae was discovered by using transcript profile sequencing and comparison．It will provide fundamental data for the relative research on molecular biology and metabolic regulation．

Key words:Keywords: Candida shehatae，xylose metabolism，ethanol fermentation，transcript profile，expressed sequence tag