基于转录组的不同火龙果品种抗性差异分析

不同的品种抗性不同,为进一步探究不同火龙果品种之间的抗性差异,为后续火龙果抗性育种提供参考,该研究利用Illumina HiSeq 2000测序平台对'普通白肉'(BR)和'厄瓜多尔黄龙'(EY)两个品种进行转录组测序分析,并参考GO Ontology、KEGG等公共数据库对差异表达基因进行功能分类与富集分析.结果表明...     

NaCl胁迫下哈茨木霉ACCC32524的转录组和代谢组分析

【目的】通过分析NaCl胁迫下哈茨木霉(Trichoderma harzianum)ACCC32524转录组和代谢组数据,研究差异表达基因及次级代谢产物的变化情况,初步探索响应NaCl胁迫的分子机制。【方法】利用Illumina HiSeq XTen高通量测序平台完成0、0.4、0.6 mol/L NaCl浓度胁迫培养下哈茨木霉ACCC32524的转录组测序,GC-TOF-MS技术完成对0mol/L和0.6mol/LNaCl胁迫培养下的差异次级代谢产物检测,利用相关软件及数据库对差异表达基因(DEGs)和次级代谢产物的注释、筛选和分类,并进行RT-qPCR验证。【结果】本研究分别得到0.4 mol/L和0.6 mol/L NaCl胁迫下417和733条差异表达基因;GO富集分析显示,分别有318和582条差异表达基因注释到生物学过程、分子功能和细胞组分3个一级分类和40个二级分类;COG分类结果表明分别有232和414条转录本为20个类别,涉及差异表达基因最多的分别为氨基酸的转运和代谢、一般功能预测、碳水化合物的转运和代谢;KEGG代谢途径分析结果表明,分别有75和96条基因归到25个代谢通路中(P≤0.05),其中涉及差异基因最多的是氨基酸的生物合成和2-氧代羧酸代谢通路。从转录组数据中共筛选出与渗透调节、离子转运、活性氧清除等22个耐盐相关基因。0 mol/L和0.6 mol/L NaCl胁迫下的代谢组数据中共筛选出101个差异次级代谢产物,包括8种积累量上调和93种下调物质,其中36个得到定性,分属于糖类、有机酸和氨基酸等9个分类中。RT-qPCR验证挑选的差异表达基因的表达量变化,均与RNA-seq分析结果一致。【结论】NaCl胁迫下引起哈茨木霉ACCC32524基因及次级代谢产物发生明显变化,细胞代谢途径发生明显偏移,这些进程共同作用减少NaCl对细胞的毒害作用,为木霉菌的耐盐机理研究提供重要信息。     

De novo transcriptome sequencing of marine-derived <Emphasis Type="Italic">Aspergillus glaucus</Emphasis> and comparative analysis of metabolic and developmental variations in response to salt stress

Aspergillus glaucus HB1-19 is a typical marine-derived fungus preferring the dependence on sea water for its growth, asexual development and polyketides biosynthesis. Therein, salt stress greatly functions even in superior to light illumination, which is also a critical regulation signal for fungi. Here, comparative RNA-seq analysis of this strain was performed under conditions of salt-stress + dark (group A), non salt-stress + dark (group B), salt-stress + light (group C). The RNA-seq generated a total of 19,024 unigenes with an average length of 1415 bp. Differentially expressed genes were very similar between group A and group C but greatly differed between group A and group B, proving that salt stress functioned superior to light illumination globally. Salt stress highly enhanced primary metabolism and activated Ras and MAPK signaling pathways. There seems no direct interaction between asexual development and polyketides biosynthesis. Salt stress inhibited terpenoids biosynthesis but showed little influences on polyketide pathway as well as other secondary metabolism pathways. These findings provide a better understanding of marine fungi adapting to marine environment. Also, it indicates that the so-called ‘salt stress-induced’ may truly be a ‘metal ions-induced’ for biosynthesis of secondary metabolites in marine fungi.     

<Emphasis Type="Italic">PpVIN2</Emphasis>, an acid invertase gene family member,is sensitive to chilling temperature and affects sucrose metabolism in postharvest peach fruit

We previously reported that expression and activity of acid invertases (AI) are increased in peach fruit under chilling stress. In order to determine which AI genes respond to chilling stress, seven AI genes, two vacuolar invertases (VINs) and five cell wall-bound invertases (CWINs), were identified and cloned. The predicted amino acid sequences of the genes contain conserved sites characteristic of plant AIs such as NDPNG/A, the sucrose-binding site, and MWECV/P, a cysteine catalytic motif. Using gene-specific primers, the expression of each gene was measured in ‘Baifeng’ and ‘Yulu’ peach fruits stored at 0, 5, 10 and 20 °C. Of the seven genes, expression of PpVIN2 was the most affected by chilling stress; the largest increases were in fruit stored at 5 °C, up to 17-fold in ‘Baifeng’ fruit, and up to 280-fold in ‘Yulu’ fruit. Overall, VIN activity was much higher than CWIN activity in stored peach fruit. In both cultivars reducing sugar content increased significantly and sucrose content decreased gradually during storage at 5 °C relative to other temperatures, and was accompanied by severe chilling injury symptoms. Thus, PpVIN2 appears to be induced by chilling and may play an important role in sucrose metabolism in peach fruit subjected to cold storage.