玉米应答干旱胁迫的转录表达谱数据挖掘及WRKY基因家族的分子进化

发布时间：2018-04-09 02:20

本文选题：玉米　切入点：干旱胁迫　出处：《西北农林科技大学》2017年硕士论文

【摘要】：干旱等非生物胁迫是严重影响植物生长发育以及后期产量的环境因素。为了适应不利环境,植物进化出复杂的应答机制,包括转录调控、表观修饰、代谢重整等。在转录调控网络中,转录因子处于中心地位,能够调节成百上千的下游基因的表达。本研究对正常和干旱胁迫条件下玉米B73三种不同组织和四个发育时期的24组转录组数据进行分析及构建共表达网络;进一步研究了玉米WRKY转录因子家族的系统进化关系与干旱应答表达谱,具体研究结果如下:1.通过转录组数据的比对、拼接和表达量计算,发现至少在一组样品中表达的基因有27885个,而52.24%(14625/27885)的基因在24组样品中都有表达。进一步差异表达分析发现了11284个差异表达基因,其中干旱胁迫下雌穗和叶片的R1时期差异表达基因数目最多,而雄穗不同时期的差异基因数目都相对较少。2.使用WGCNA包将差异表达基因划分为10个模块。不同模块与基因的组织时期特异性表达有关,暗示着不同的功能。进一步GO富集分析发现这些功能包括叶绿体光合作用、酶活性、花粉管生长、膜转运、细胞壁、胁迫响应、转录调控、水解酶活性等。共表达网络包含844个枢纽基因,15.4%的枢纽基因存在全基因组复制事件,基因复制产生的同模块的枢纽基因对之间的表达相关系数更高,说明它们功能趋向于保守。3.通过结合已知的调控网络,聚焦于共表达网络中发挥枢纽作用的转录因子。发现bHLH,NAC,C2H2等转录因子家族成员在玉米应答干旱胁迫和发育中扮演着双重角色。4.WRKY转录因子是植物特有的转录因子,在植物应答生物或非生物胁迫时具有重要功能。我们鉴定出玉米基因组含有120个WRKY基因家族成员,基因结构和蛋白序列分析表明不同WRKY亚家族具有各自独特的特征;利用公共数据库中的基因芯片数据进行表达谱分析,发现8个WRKY基因响应干旱胁迫;RNA-seq数据分析表明58个WRKY基因响应干旱胁迫;利用实时荧光定量PCR技术鉴定出7个基因应答干旱胁迫;进一步对10个WRKY基因进行启动子顺式元件分析,发现10个基因的启动子区域均含有应答干旱的顺式元件;蛋白质相互作用分析表明21个差异表达的WRKY转录因子间可能存在互作关系。
[Abstract]:Abiotic stress, such as drought, is a serious environmental factor affecting plant growth and late yield.In order to adapt to adverse environment, plants have evolved complex response mechanisms, including transcriptional regulation, epigenetic modification, metabolic reorganization, and so on.In the transcriptional regulatory network, transcription factors are central and can regulate the expression of hundreds of downstream genes.In this study, 24 sets of transcriptome data of three different tissues and four developmental stages of maize B73 under normal and drought stress conditions were analyzed and coexpression networks were constructed.The phylogenetic relationship and drought response expression profiles of maize WRKY transcription factor family were further studied. The results are as follows: 1.By comparison of transcriptome data, splicing and expression calculation, we found that 27885 genes were expressed in at least one set of samples, while 52.24625 / 27885) genes were expressed in 24 groups of samples.Further differential expression analysis revealed 11284 differentially expressed genes, in which the number of differentially expressed genes in female ear and leaf at R1 stage was the highest, while the number of differentially expressed genes in different stages of male ear was relatively small.The differentially expressed genes were divided into 10 modules using WGCNA package.Different modules are related to the specific expression of genes during tissue stage, suggesting different functions.Further go enrichment analysis showed that these functions included chloroplast photosynthesis, enzyme activity, pollen tube growth, membrane transport, cell wall, stress response, transcriptional regulation, hydrolase activity and so on.In the coexpression network, 15.4% of the hinge genes contained 844 pivotal genes, and the gene replication generated by gene replication had higher expression correlation coefficient between the hinge gene pairs of the same module, which indicated that their function tended to be conservative. 3.By combining known regulatory networks, it focuses on transcription factors that play a pivotal role in coexpression networks.It was found that the members of the transcription factor family such as BHLHHN NACN C2H2 play a dual role in maize drought response and development. 4. WRKY transcription factors are plant specific transcription factors and play an important role in plant response to abiotic or abiotic stress.We identified 120 members of WRKY gene family in maize genome. The analysis of gene structure and protein sequence showed that different WRKY subfamilies had their own unique characteristics.Eight WRKY genes were found to be responsive to drought stress by RNA-seq data analysis, and 7 genes were identified by real-time fluorescence quantitative PCR.Further analysis of 10 WRKY gene promoter cis-elements showed that all the promoter regions of the 10 genes contained cis-elements in response to drought.Protein interaction analysis showed that there might be interaction among 21 differentially expressed WRKY transcription factors.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S513;Q943.2

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