玉米中介体亚基MED7基因的克隆及初步功能分析

发布时间：2018-03-01 19:24

本文关键词： 转录中介体 MED7 ABA 基因表达抗逆性分析　出处：《中国农业科学院》2016年硕士论文　论文类型：学位论文

【摘要】：玉米是重要的粮食作物。玉米产量常会受到冷、热、旱、涝、盐等不良环境的影响,为适应环境改变,植物进化出了一系列应答机制。挖掘玉米与非生物逆境胁迫应答及生长发育相关的基因,为玉米增产抗逆育种提供基因资源和理论基础非常必要。研究表明,在植物不同生长发育阶段包括花期及籽粒形成过程中,转录中介体都起到非常重要的作用。此外,转录中介体通过激活植物自身的防卫机制来参与胁迫应答反应。本论文从玉米野生型Q319 cDNA中扩增出了与拟南芥具有高度同源性的转录中介体亚基基因MED7-1、MED7-2。通过分析MED7-1、MED7-2的发育和逆境诱导表达谱、转基因拟南芥对干旱和高盐胁迫的抗性,旨在对该中介亚基在玉米生长发育过程中的功能进行初步的分析。本论文取得的主要结论如下:(1)MED7-1、MED7-2在玉米种子萌发初期,营养生长阶段不同时期的根和叶,未成熟雄穗、吐丝雌穗和授粉后不同时期的籽粒和胚乳中均有表达,但其表达量在不同发育时期不同组织中存在显著差异。(2)MED7-1、MED7-2在玉米幼嫩叶片中的表达受BR、IAA、GA3的诱导上调,受ABA、盐和干旱胁迫的影响表达下调。(3)MED7-1过表达拟南芥种子萌发及根伸长对ABA的敏感性降低,MED7-1过表达拟南芥对干旱和高盐胁迫的耐受性降低;MED7-2转基因拟南芥对干旱、盐等胁迫的耐受性降低,但较转MED7-1植株不明显。(4)构建了MED7-1和MED7-2的过表达、RNAi和FLAG融合蛋白等玉米表达载体并转化玉米,获得了一部分转基因玉米T1代株系,为进一步在玉米内源系统中研究MED7的功能和作用机制奠定了基础。上述研究结果表明,玉米转录中介亚基MED7基因在植物逆境应答过程中发挥调控作用,为植物激素的转录调控机理提供了一个新的切入点,为进一步研究玉米中介体的功能提供一些依据。
[Abstract]:Corn is an important food crop. Corn yield is often affected by cold, heat, drought, waterlogging, salt and other adverse environment, to adapt to environmental changes, Plants have evolved a series of response mechanisms. It is necessary to excavate genes related to abiotic stress response and growth and development in order to provide genetic resources and theoretical basis for maize breeding to increase yield and resist stress. Transcriptional intermediaries play a very important role in plant growth and development, including flowering and grain formation. Transcriptional intermediaries are involved in the stress response by activating the plant's own defense mechanism. In this paper, we amplified the transcription intermediary subunit MED7-1 and MED7-2from maize wild type Q319 cDNA with high homology with Arabidopsis thaliana. The developmental and stress-induced expression profiles of MED7-1 and MED7-2, The resistance of transgenic Arabidopsis thaliana to drought and high salt stress was studied in order to analyze the function of the intermediate subunit during maize growth and development. Root and leaf, immature male ear, female spikelet and grain and endosperm were expressed in different stages of vegetative growth. However, there were significant differences in the expression of MED7-1 and MED7-2 in different tissues of different developmental stages. The expression of MED7-2 in young leaves of maize was up-regulated by BRGA-GA3. Overexpression of Arabidopsis thaliana seed germination and root elongation sensitivity to ABA decreased the tolerance of Arabidopsis thaliana to drought and high salt stress. Maize expression vectors such as MED7-1 and MED7-2 were constructed and transformed into maize, and some transgenic maize T1 lines were obtained. These results indicate that MED7 gene plays a regulatory role in plant stress response. It provides a new entry point for the transcriptional regulation mechanism of plant hormones and provides some basis for further study on the function of maize intermediaries.
【学位授予单位】：中国农业科学院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S513;Q943.2

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