| 里氏木霉不同糖苷水解酶基因转录水平比较分析 |
| Transcriptional analysis of different glycoside hydrolase genes in Trichoderma reesei |
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| 中文关键词:转录组测序，纤维素酶，实时荧光定量PCR，α-甘露糖苷酶 |
| 英文关键词:RNA-seq, cellulase, real-time PCR, α-mannosidase |
| 基金项目:福建省发改委产业化关键技术项目（闽发改投资[2009]958号）；国家自然科学基金（No. 30970073）；973项目（No. 2011CB707402）；中国科学院重大专项（No. KSCX1-YW-11B3） |
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| 中文摘要: |
| 以前期里氏木霉RNA-seq中发现的7个糖苷水解酶基因为对象，分析其不同条件下的表达特性，以期为寻找新的纤维素降解功能酶提供证据。运用生物信息学方法，分析了7个基因可能的编码产物和结构特征。以不同的产纤维素酶菌株（QM 9414、RUT C30）为材料，采用实时荧光定量PCR，对7个糖苷水解酶基因（编号4–10）在各种碳源条件下转录情况与主要的3个纤维素酶基因cbh1，cbh2，egl1（编号1–3）进行了比较分析。信息学分析表明，7个基因编码蛋白分属于GH47（4号、5号），GH92（6–8号），GH16（9号），GH31（10号）糖苷水解酶家族，具有典型的信号肽序列。cbh1，cbh2，egl1基因在纤维素酶诱导条件下，转录水平均表现显著的增加，上调倍数以QM 9414菌株表现的最高。QM 9414菌株中，cbh1，cbh2，egl1基因在纤维素条件下的上调倍数显著高于乳糖，3个基因在RUT C30菌株中的转录水平则显示乳糖条件下上调幅度更大。7个糖苷水解酶基因也存在类似的情况，而且编码α-甘露糖苷酶和内切β-葡聚糖酶的8号、9号基因上调倍数在纤维素酶诱导条件下仅次于纤维素酶基因，而以甘油为碳源条件下，8号、9号基因上调倍数高于纤维素酶基因。4号基因在上述碳源条件下，转录水平变化不大。结果表明：4号基因可能是组成型表达。基因5、6、7、8、9、10的表达呈现明显的菌株和碳源依赖性，且在纤维素酶诱导条件下基本上是和3个纤维素酶基因共转录的。 |
| 英文摘要: |
| Transcriptional analysis was performed for seven glycoside hydrolase genes identified by our previously RNA-seq, aiming to identify new genes whose protein products promote the lignocellulose degradation, and provide rational targets for optimizing cellulase system. The structure features of proteins encoded by selected seven genes were predicted via bioinformatic analysis. Quantitative real time PCR was used to analyze the transcriptional levels of seven genes encoding glycoside hydrolases (gene number designated as No. 4–10) along with three major cellulase genes (gene No. 1–3) of cbh1, cbh2 and egl1, under different carbon sources in QM 9414 and RUT C30 strains, respectively. Bioinformatic analysis showed that the protein products of seven genes belong to glycoside hydrolase family 47 (No. 4 and 5), 92 (No. 6–8), 16 (No. 9), and 31 (No. 10), respectively, and contain typical signal peptide sequences. The transcriptional levels of cbh1, cbh2, egl1 were significantly increased under induction of cellulase. Compared to lactose, cellulose induced higher fold change of the three genes in QM 9414 strain on mRNA level. However, in RUT C30 strain, mRNA abundances of the three genes were more abundant when the fungus was grown on lactose than that on cellulose as sole carbon source. The transcriptional levels of seven glycoside hydrolase genes showed the same tendency as those of the three major cellulase genes. The fold changes of gene No. 8 encoding α-mannosidase as well as gene No. 9 encoding β-glucanase were secondary to those of three major cellulase genes under the cellulose induction. However, the transcriptional levels of gene No. 8 and 9 showed more significant alterations when Trichoderma reesei grew on glycerol than that on cellulose. No significant alteration of transcriptional level was observed for gene No. 4, which is probably constitutively expressed by the fungus. The results indicated that the expressions of gene No. 5–10 were significantly dependent on carbon sources and strains. In addition, we found that seven glycoside hydrolase genes and three major cellulase genes were coordinately induced by cellulose and lactose. |
| 尉洪涛,陈秀珍,陈飞,黄建忠,董志扬. 里氏木霉不同糖苷水解酶基因转录水平比较分析[J]. 菌物学报, 2012, 31(5): 717-726 |
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