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| 红砂响应干旱和UV-B辐射双重胁迫的基因转录表达分析 | |
| 其他题名 | Analysis of gene transcriptional expression in Reaumuria soongorica under the combined stress of drought and UV-B radiation |
| 刘丹 | |
| 出版年 | 2017 |
| 学位类型 | 硕士 |
| 导师 | 刘玉冰 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 红砂是多年生超旱生小灌木，广泛分布于我国西北干旱区，是荒漠灌丛植被的主要优势种和建群种。自然生境中红砂同时遭受多重环境因子的胁迫，而对其响应多重胁迫因子的应答机理研究目前很少。本文利用数字基因表达谱技术和转录组学数据分析了红砂在干旱（P）、UV-B辐射（U）以及干旱和UV-B辐射双重胁迫（UP）下基因在转录水平表达响应的差异，探讨荒漠植物对多重胁迫因子的适应机理。结果显示：（1）不同胁迫处理材料与对照材料相比，P、U和UP各有1325、2150和1369个差异表达基因（DEGs），且不同胁迫中下调表达基因总数多于上调表达的。三种胁迫下只有383个DEGs同时发生差异表达，但双重胁迫诱导了356个上调和248个下调的特异表达基因。从诱导基因的差异表达量来看，多数基因的差异表达量集中在2-5倍，同时也诱导了少数基因的高度表达（高于100倍）。（2）差异表达基因的GO（Gene Ontology）功能富集显著性分析发现三种胁迫处理下GO本体信息条目表现出高度的相似性，但双重胁迫相比单因子胁迫，固碳作用、光系统Ⅱ等生物过程的表达显著性富集。KEGG（Kyoto Encyclopedia of Genes and Genomes）代谢通路分析表明，不同的代谢途径对不同的胁迫处理表现出不同程度的响应。（3）三种胁迫处理不仅诱导了响应干旱和UV-B辐射的基因发生差异表达，同时诱导了响应其他胁迫因子的基因显著差异性表达，包括非生物因子外源激素、金属离子等和生物因子。诱导的DEGs既有响应双重胁迫特异性表达的，也有与单因子胁迫共同表达的，但总体来说，下调表达的基因数量多于上调表达的。参与响应的差异表达基因编码巨噬细胞蛋白、线虫抗性蛋白、衰老相关蛋白、丙氨酰-tRNA合成酶、谷氨酰胺合成酶、核糖核蛋白等。（4）胁迫诱导了不同功能基因以及不同代谢途径基因的差异性表达。不同胁迫下红砂体内功能蛋白差异表达基因（编码抗氧化系统酶和渗透调节物质）和调控蛋白差异表达基因（编码蛋白激酶和转录因子）表达量均下调，这些基因的表达直接参与保护细胞或体内信号转导等过程。三种胁迫下光合作用代谢途径的差异表达基因（编码氧捕获增强蛋白、ATP合成酶、叶绿素a/b结合蛋白和Rubisco小亚基等）整体表达量下调，双重胁迫下的表达量下调更显著，表明双重胁迫对光合作用的抑制作用更明显。而黄酮类代谢途径的关键酶基因（F3H、FLS、CHS、LAR、CHI和F3’5’H等）表达量明显上调，表明黄酮合成代谢途径在红砂适应这三种胁迫过程中均发挥了重要的调控作用。研究结果表明，双重胁迫诱导基因表达的变化并非两种单因子胁迫简单相加效应，红砂在基因转录水平对单因子胁迫和双重胁迫的响应过程存在很大程度的差异，且不同胁迫的响应基因之间存在明显的协同性表达。不同胁迫均诱导了功能蛋白基因、调控基因、光合代谢途径和黄酮合成代谢途径基因的显著差异表达，双重胁迫相对于单因子胁迫，明显增加了对光合能力的抑制，但功能蛋白基因和代谢调控途径表现出较一致的响应。 |
| 英文摘要 | Reaumuria soongorica (Pall.) Maxim., a perennial and super xerophytic semi-shrub widely distributed in arid areas of northerwest China, is the main dominant and constructive species of shrub vegetation in desert ecosystem. So it is subjected to multiple environmental factors in its natural habitats. However, little information is available about the responsive mechanism of Reaumuria soongorica to multiple stresses until now. In the present study, we analyzed the difference of the gene expression at the transcription level in desert plant Reaumuria soongorica under drought (P), enhanced UV-B radiation (U) and their combination of the two (UP) by using the digital gene expression profiling technique and the data of transcriptomics. Our aim is to explore the adaptation mechanism of desert plants response to multiple stresses. The results showed that:(1) Compared with the control materials, there were 1325, 2150 and 1369 differentially expressed genes (DEGs) in the group of P, U and UP, respectively. The numbers of down-regulated genes were higher than that of up-regulated in stress treatment groups. Only 383 identical DEGs were differentially expressed at the same time under three conditions, and there were 356 up-regulated and 248 down-regulated genes induced specifically by combined stresses (UP). Among these DEGs, most of the gene expression amount changed from 2 to 5 fold, and only few genes were found highly expressed (more than 100 fold).(2) Analysis of Gene Ontology function enrichment showed that its items showed a high similar degree among three treatments, but some biological processes such as carbon fixation and photosystem Ⅱ expressed significantly under UP than U or P. Analysis of Kyoto Encyclopedia of Genes and Genomes pathway enrichment showed that different metabolic pathways had different expression levels in response to different stresses.(3) Stresses of P, U and UP not only induced DEGs in response to drought and UV-B radiation, but also induced a significant difference of gene expression in response to other stresses, including abiotic factors such as hormone stimulus, metal ion and other biological factors. Among these DEGs, some were responsed specificly to UP and others were induced by single factor P or U, and the numbers of down-rugulated genes were higher than that of up-regualated. These DEGs encoded proteins such as macrophage protein, nematode resistance protein, senescence-related protein, alanyl-tRNA synthetase, glutamine synthase and ribonucleoprotein, etc..(4) DEGs induced by P, U and UP had different functions and involved in different metabolic pathways. DEGs encoding functional proteins (antioxidant enzymes and osmotic adjustment substance) and regulatory proteins (protein kinases and transcription factors) were down regulated under different stresses in Reaumuria soongorica. These genes directly functioned in the process of cell protection or parctipated signal transduction under stress. The expression amount of DEGs in photosynthetic pathway (encoding oxygen-evolving enhancer protein, ATP synthase, chlorophyll a/b binding protein, ribulose 1,5-bisphosphate carboxylase/oxygenase small subunit, etc.) decreases under three treatments. The higher down-regulation of gene expression was exhibited under UP, indicating that the inhibition level of photosynthesis by UP was more serious than by one factor. However, gene expression levels of key enzymes in flavonoid metabolic pathway (F3H, FLS, CHS, LAR, CHI, F3’5’H, etc.) were significantly up-regulated, suggested that flavonoid biosynthetic pathway played important roles in the adaptation of Reaumuria soongorica under stresses.These results suggested that gene expression response to combined stresses (UP) was not the simple additive effect of the two single stress. There were significant differences in gene transcription level between single stress and combined stresses in Reaumuria soongorica. Moreover, the effect of “cross-talk” with other stresses was found under these treatments. Different stresses indeced DEGs including functional genes, regulatory genes, and genes involved in photosynthetic metabolism pathway and flavonoid biosynthetic pathway. Compared with the single stress, the inhibition of photosynthesis was increased under UP, but fuctional genes, regulatory genes and flavonoid metabolism pathway showed a consistent response under different treatments. |
| 中文关键词 | 红砂 ; 干旱胁迫 ; UV-B辐射 ; 双重胁迫 ; 数字基因表达谱 |
| 英文关键词 | Reaumuria soongorica (Pall.) Maxim. drought stress UV-B radiation two factors stress digital gene expression profiling |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287956 |
| 推荐引用方式 GB/T 7714 | 刘丹. 红砂响应干旱和UV-B辐射双重胁迫的基因转录表达分析[D]. 中国科学院大学,2017. |
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