干旱胁迫对谷子DNA胞嘧啶甲基化变异的影响研究

发布时间：2018-05-04 05:00

本文选题：谷子 + 干旱　；参考：《辽宁大学》2017年硕士论文

【摘要】：干旱(Drought)是全世界最普遍的自然现象,并且是对农作物伤害最严重的胁迫之一。近年来,人们对干旱引起的作物减产问题越来越重视,抗旱研究已成为全球的研究热点。植物对干旱的响应体现在生长发育的各个阶段。许多研究结果发现表观遗传修饰可以影响植物的生长发育。尤其是DNA甲基化作为表观遗传修饰的重要组成成员,对于基因表达的调控,以及基因组防御等过程有重要作用。已有研究发现逆境胁迫可以引起植物DNA甲基化水平以及模式的变异。为了对植物响应干旱胁迫的表观遗传效应进一步研究,并为了对干旱胁迫表观遗传机制的了解更加全面,发现植物可能的抗旱功能基因,本研究以抗旱种质谷子品种豫谷1为实验材料,利用20%PEG模拟干旱胁迫条件,对谷子胁迫处理2h、6h、12h、24h、3d、5d后,随机混取各个时间点的叶片DNA,运用MSAP技术进行DNA甲基化水平和模式检测,并且对干旱胁迫引起的变异进行分析。本研究共获得1520个清晰的位点,扩增条带1476-1502条,甲基化水平的变化范围为10.92%-11.05%,其中半甲基化位点30-57个,占总位点的1.97%-3.75%,全甲基化位点110-138个,占总位点的7.24%-9.08%,表明甲基化在谷子中甲基化模式更多的是全甲基化。根据甲基化位点分析发现,CG位点的甲基化水平比CNG位点以及CG/CNG位点分别高出3.9%和3.7%,说明甲基化多数发生在CG位点上。干旱胁迫引起的甲基化变异位点占总位点的0.52%-2.11%,其中发生超甲基化变化的位点占总位点的0.13%-0.54%,而发生去甲基化的位点占总位点的0.13%-1.78%。根据发生甲基化变异的位点分析发现,甲基化变异主要发生在CNG位点,CNG位点发生超甲基化的概率为0.07%-0.20%,而发生去甲基化的概率为0.13%-1.64%。对甲基化变异带进行回收测序,Blast N和Blast X分析结果表明,干旱胁迫引起的谷子甲基化变异序列与已知谷子中过氧化酶基因同源,表明谷子在应对干旱胁迫时,甲基化变异与植物体内相关蛋白基因相互作用从而适应胁迫。
[Abstract]:Drought Droughtis the most common natural phenomenon in the world and is one of the most serious stresses on crops. In recent years, people pay more and more attention to crop yield reduction caused by drought, and drought resistance research has become a global research hotspot. The response of plants to drought occurs at all stages of growth and development. Many studies have found that epigenetic modification can affect plant growth and development. Especially, DNA methylation is an important component of epigenetic modification, which plays an important role in the regulation of gene expression and genome defense. It has been found that stress stress can induce the variation of DNA methylation level and pattern in plants. In order to further study the epigenetic effect of plant response to drought stress and to understand the epigenetic mechanism of drought stress, the possible drought resistance functional genes were found. In this study, the drought-resistant germplasm variety Yugu 1 was used as the experimental material, and 20%PEG was used to simulate the drought stress condition. The leaf DNA of each time point was randomly mixed for 5 days after 2 h ~ 6 h ~ (12) h ~ (24) d ~ (-1) stress, and the DNA methylation level and model were detected by MSAP technique. The variation caused by drought stress was analyzed. In this study, 1 520 clear sites were obtained and 1476-1502 bands were amplified. The range of methylation level was 10.92-11.05, of which 30-57 were semi-methylation sites, which accounted for 1.97-3.75 and 110-138 completely methylated sites. 7.24- 9.08% of the total sites indicated that the methylation pattern in millet was more total methylation. According to the analysis of methylation site, the methylation level of CG site was 3.9% and 3.7% higher than that of CNG site and CG/CNG site, respectively, indicating that most of the methylation occurred at CG site. The methylation variation sites caused by drought stress accounted for 0.52-2.11 of the total sites, among which the hypermethylation sites accounted for 0.13-0.54 of the total sites, while the demethylation sites accounted for 0.13-1.78 sites of the total sites. According to the site analysis of methylation mutation, the probability of hypermethylation occurred mainly at CNG locus was 0.07-0.20, and the probability of demethylation was 0.13- 1.64g. The methylation mutation bands were recovered and sequenced by blast N and Blast X analysis. The results showed that the methylation variation sequence of millet caused by drought stress was homologous to the known peroxidase gene in millet, which indicated that millet was in response to drought stress. Methylation variation interacts with plant associated protein genes to adapt to stress.
【学位授予单位】：辽宁大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S515;S423

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