兰州大学机构库 >生命科学学院
高山离子芥耐冷机理的转录组学研究
Alternative TitleTranscriptome analysis of cold tolerance mechanisms of Chorispora bungeana
谭玲玲
Thesis Advisor安黎哲 ; 赵志光
2012-12-05
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
Keyword高山植物 高山离子芥 耐寒性 抗冻性 Illumina深度测序 转录组
Abstract   植物对低温具有耐受作用,但其机理尚不甚清楚。在转录水平上,虽然有大量研究对模式植物拟南芥耐受低温的机理进行了较深入的研究,但只有少量的研究是以具有天然耐寒抗冻机理的植物进行的。由于高山环境的日气温变化频繁而且变化幅度很大,低温胁迫经常发生,高山植物可能通过独特的低温耐受机理来适应这种多变的环境。    高山离子芥是一种具有强耐冷、抗冻能力的高山冰缘植物,为研究其耐冷的分子机理,本论文使用Illumina深度测序的方法研究了冷胁迫下高山离子芥的转录组,并通过生物信息学方法比较了高山离子芥和拟南芥冷调节基因的GO功能和KEGG代谢途径网络。获得结果如下:    1、以对照(22℃)和冷胁迫(2℃)处理的高山离子芥为材料,本论文分别构建两个cDNA文库并使用Illumina技术进行了转录组测序。通过基因从头拼接的方法,我们获得了高山离子芥的54,870个unigene(cDNA序列),其中冷胁迫上调基因有3,484个,下调基因有4,571个。选择表达量变化最大的20个冷胁迫上调基因进行了荧光定量PCR验证,其中有18个基因的表达趋势与转录组分析结果相一致,表明所获得的转录组表达分析结果具有很高的准确性。    2、通过比较分析高山离子芥和拟南芥冷调节基因的GO功能和KEGG代谢途径网络,我们发现高山离子芥和拟南芥冷调节基因所参与的生物学过程和具有的分子功能上有很多共同的特点,参与基因转录过程和相关的转录因子基因在两种植物的冷胁迫上调基因中均显著富集;大量参与胁迫响应的基因被冷胁迫诱导,如:参与低温胁迫、水分胁迫、盐胁迫、氧化胁迫、UV-B胁迫的基因,参与损伤、抗病等反应的基因,以及参与脱落酸和水杨酸应答基因。本论文的分析还发现高山离子芥和拟南芥冷胁迫诱导基因中均富集了响应Karrikins的基因,这种新的植物生长调节物质可能参与了植物冷胁迫响应。    3、本论文的研究结果同时也表明高山离子芥和拟南芥的冷胁迫响应在转录水平上有极大的不同。在拟南芥中,参与冷驯化的基因被冷胁迫诱导并在冷胁迫上调基因群中富集;然而,类似功能的基因在高山离子芥冷胁迫转录组上调基因中并没有显著富集。此外,在拟南芥中,CBF转录因子家族的基因受冷胁迫诱导表达;但是高山离子芥冷胁迫诱导的基因中并没有CBF基因家族的成员存在。另一方面,在高山离子芥转录组中,参与蛋白质磷酸化和泛素化的基因在冷胁迫诱导基因中显著富集,但在拟南芥转录组分析中没有发现该现象。    综合以上结果,本论文首次对高山冰缘植物高山离子芥进行了转录组分析,获得了大量的冷调节基因转录组水平的比较分析表明:高山离子芥与拟南芥在冷胁迫响应或耐受机理上可能有很大的差异;冷驯化可能并不是高山离子芥低温耐受的主要机制;激活蛋白质磷酸化和泛素化可能是高山离子芥快速适应低温环境的机理之一。    本论文的研究结果丰富了植物低温耐受机理的研究理论,为通过转基因手段提高作物耐受突发性寒冻灾害能力提供了新的指导理论,为进一步探索植物的低温耐受机理和功能基因挖掘提供了丰富的特殊基因资源。
Other AbstractThe plant tolerance mechanisms to low temperature have been studied extensively in the model plant Arabidopsis at the transcriptional level. However, few studies were carried out in plants with strong inherited cold tolerance. Chorispora bungeana is a subnival alpine plant possessing strong cold tolerance mechanisms. To get a deeper insight into its cold tolerance mechanisms, the transcriptome profiles of chilling-treated C. bungeana seedlings were analyzed by Illumina deep-sequencing and compared with Arabidopsis. Two cDNA libraries constructed from mRNAs of control and chilling-treated seedlings were sequenced by Illumina technology. A total of 54,870 unigenes were obtained by de novo assembly, and 3,484 chilling up-regulated and 4,571 down-regulated unigenes were identified. The expressions of 18 out of top 20 up-regulated unigenes were confirmed by qPCR analysis. Functional network analysis of the up-regulated genes revealed some common biological processes, including cold responses, and molecular functions in C. bungeana and Arabidopsis responding to chilling. Karrikins were found as new plant growth regulators involved in chilling responses of C. bungeana and Arabidopsis. However, genes involved in cold acclimation were enriched in chilling up-regulated genes in Arabidopsis but not in C. bungeana. In addition, although transcription activations were stimulated in both C. bungeana and Arabidopsis, no CBF putative ortholog was up-regulated in C. bungeana while CBF2 and CBF3 were chilling up-regulated in Arabidopsis. On the other hand, up-regulated genes related to protein phosphorylation and auto-ubiquitination processes were over-represented in C. bungeana but not in Arabidopsis. We conducted the first deep-sequencing transcriptome profiling and chilling stress regulatory network analysis of C. bungeana, a subnival alpine plant with inherited cold tolerance. Comparative transcriptome analysis suggests that cold acclimation is not a major chilling tolerance mechanism of C. bungeana. Activation of protein phosphorylation and ubiquitination may confer chilling tolerance to C. bungeana in a more rapid and flexible way than cold acclimation. Such differences may have contributed to the differences in cold tolerance between C. bungeana and Arabidopsis. The results presented in this paper will be informative for gene discovery and the molecular mechanisms related to plant cold tolerance.
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/221364
Collection生命科学学院
Recommended Citation
GB/T 7714
谭玲玲. 高山离子芥耐冷机理的转录组学研究[D]. 兰州. 兰州大学,2012.
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