低温胁迫对冰菜转录组水平响应分析

Analysis of Transcriptome Response to Low Temperature Stress in Mesembryanthemum crystallinum Linn

利用二代高通量测序技术对低温胁迫处理的冰菜进行测序,构建冰菜转录组数据库。分别得到24.13 Gb有效数据和24 045条Unigene的注释,得到DEGs 1 902个(T0 vs T1)和2 134个(T0 vs T2)。T0 vs T1组和T0 vs T2组分别有40和41个功能小类化归GO数据库;分别有20和24个功能分类注释到KOG数据库;155和272条基因注释到KEGG数据库,并分别富集在74和105条代谢通路。T0 vs T1组DEGs主要注释到植物信号转导等4个代谢通路;T0 vs T2组DEGs注释到苯丙醇类生物合成等11个代谢通路,其中正向影响代谢途径:丙酮醇类生物合成、嘌呤代谢、谷胱甘肽代谢、脂肪酸代谢、类黄酮代谢、氨基酸的生物合成代谢途径等;负向影响代谢途径:植物-病原互作、植物激素信号转导、淀粉和蔗糖代谢等途径。通过对淀粉和蔗糖代谢途径关键基因分析表明:低温胁迫1 h (T1),海藻糖6-磷酸合酶、海藻糖-6-磷酸酯酶、β-淀粉酶、葡萄糖-1-磷酸腺苷酰转移酶、糖原磷酸化酶等5个关键基因表现为上调表达,未见下调表达基因;低温胁迫36 h (T2),海藻糖-6-磷酸合酶、己糖激酶、β-淀粉酶等3个关键基因上调表达,葡萄糖内酯-1,3-β-葡萄糖苷酶基因下调表达。选取淀粉和蔗糖代谢途径中8个DEGs,经RT-qPCR分析,8个DEGs的相对表达量与转录组表达水平相符。

The second generation of high throughput sequencing technology was used to sequence Mesembryanthemum crystallinum under low temperature stress and to construct transcriptome database.24.13 Gb of valid data and 24 045 annotations of Unigene were was obtained.DEGs of 1 902(T0 vs T1) and 2 134(T0 vs T2) were obtained.Two groups of DEGs were classified into 40 and 41 functional small categories respectively by GO database and were obtained respectively 20 and 24 functional categories by KOG database and were annotated 55 and 272 genes by comparing DEGs with KEGG database,which were enriched in 74 and 105 metabolic pathways respectively.DEGs of T0 vs T1 group mainly annotated to 4 metabolic pathways;DEGs of T0 vs T2 group mainly annotated to 11 metabolic pathways.It were showed that there were the metabolic pathways of positive correlation:acetone alcohol biosynthesis,purine metabolism,glutathione metabolism,fatty acid metabolism,brass metabolism,amino acid biosynthesis and other metabolic pathways,and the metabolic pathways of negative correlation:plant-pathogen interaction,plant hormone signal transduction,starch and sucrose metabolism.The key genes of starch and sucrose metabolism pathway were analyzed:the expression of 5 key genes,such as trehalose 6-phosphate synthase,trehalose-6-phosphatase,beta-amylase,glucose-1-adenosine phosphate transferase and glycogen phosphorylase,were up-regulated,but down-regulated gene was not observed during T1(1 h) of low-temperature stress;Three key genes of trehalose-6-phosphosynthase,hexokinase and beta-amylase,were up-regulated and the glucolactone-1,3-beta-glucosidase gene was down-regulated under low temperature stress at T2(36 h).Eight DEGs in starch and sucrose metabolism pathway were selected and analyzed by Quantitative real-time PCR.The relative expression level of 8 DEGs was consistent with the transcriptome expression profile analysis.