水稻谷氨酰胺合成酶基因表达特性及其与启动子结构关系分析

发布时间：2018-06-05 17:21

本文选题：水稻 + 超亲变异系　；参考：《东北农业大学》2017年硕士论文

【摘要】：谷氨酰胺合成酶(GS)活性大小或基因表达量与植物蛋白质含量高低有密切关系。启动子作为基因转录水平上的重要调控元件,控制着基因表达的时间和空间特性。本研究选用籽粒蛋白含量有显著差异的籼稻品种及粳稻品种进行盆栽试验,分析灌浆不同时期籽粒蛋白质含量、GS活性和基因表达量及GS同工型基因启动子序列和结构变化及其与转录表达量间的关系,旨在深入了解GS基因启动子的结构特点及其与转录水平上的调控关系,进而为解析基因转录水平的分子调控机理提供理论依据。研究结果表明:蛋白质含量差异显著的品种间杂交后代通过定向选择可以获得超亲变异的后代。蛋白质含量高的基因型在灌浆各时期积累的蛋白质量始终高于蛋白质含量低的基因型,基因型控制籽粒蛋白质积累量的高低。灌浆不同时期籼稻品种在籽粒和功能叶片中谷氨酰胺合成酶活性均较超亲变异系子代及亲本高,并且籽粒蛋白质含量超亲子代及亲本均比蛋白质含量低的子代和亲本谷氨酰胺合成酶活性高。GS同工型基因的表达存在着组织特异性,GS1;1基因和GS1;2基因在籽粒和叶片中都表达;GS1;3基因只在籽粒中、GS2基因只在叶片中大量表达。灌浆不同时期高蛋白质含量品种的表达量高于低蛋白质含量品种,Os GS同工型基因表达量与酶活性和籽粒蛋白质含量高低有密切关系。籽粒和叶片中GS酶活性与蛋白质含量在灌浆不同时期都呈正相关,籽粒GS1;1基因表达量与蛋白质含量间在灌浆前期和中期都呈正相关,在灌浆不同时期叶片GS1;1和GS2及籽粒GS1;3基因的表达量与蛋白质含量间都呈正相关,灌浆中期的叶片GS1;2基因表达量对籽粒蛋白质积累影响很大。籽粒蛋白质含量有显著差异的品种间GS同工型基因启动子序列的同源性高达99%以上;品种间有性杂交子代GS同工型基因的启动子序列可发生碱基的变化,但没有导致启动子核心元件发生变化。在调控元件数量和功能上GS同工型基因的启动子保守性很强,启动子在结构和功能上不易发生遗传变异,籽粒GS同工型基因表达量的变化受GS基因启动子的调控影响很小。GS同工型基因启动子结构并不完全一致,不同基因启动子在调控元件数量上有明显的差异,但不同品种间GS同工型基因启动子结构非常一致,GS同工型基因的表达与否和程度与多种环境因素有关系。
[Abstract]:The activity of glutamine synthase (GSH) or the amount of gene expression were closely related to the content of plant protein. As an important regulatory element at the level of gene transcription, promoter controls the temporal and spatial characteristics of gene expression. In this study, indica and japonica rice varieties with significant difference in grain protein content were selected for pot experiment. The changes of GS activity and gene expression, the sequence and structure of GS isotype gene promoter and the relationship between GS activity and transcriptional expression were analyzed at different grain filling stages. The aim of this study was to understand the structural characteristics of GS gene promoter and its relationship with transcriptional regulation in order to provide theoretical basis for analyzing the molecular regulation mechanism of GS gene transcriptional level. The results showed that cross progenies with significant difference in protein content could be obtained by directional selection. The amount of protein accumulated by genotype with high protein content was always higher than that of genotype with low protein content at each filling stage, and genotype controlled the accumulation of protein in grain. The activity of glutamine synthase in grain and functional leaves of indica rice varieties at different stages of grain filling was higher than that of progenies and parents of superparent variant lines. Moreover, the expression of glutathione synthase isotype genes in grain protein content superparents and parents were higher than those in offspring and parents with lower protein content. There was tissue specific expression of GS1G-1 gene and GS12 gene in grain and leaf. Zhondu expressed only in grains, and GS2 gene was only expressed in leaves. The expression of OS-GS isotype gene in high protein content variety was higher than that in low protein content variety at different filling stage, which was closely related to enzyme activity and grain protein content. There was a positive correlation between GS enzyme activity and protein content in grain and leaf at different stages of grain filling, and there was a positive correlation between GS1- 1 gene expression and protein content in early and middle grain filling stage. There was a positive correlation between the protein content and the expression of GS1F-1, GS2 and GS1T3 in the leaves at different filling stages, and the expression of GS1O2 in the leaves at the middle stage of grain filling had a great effect on the protein accumulation in the grain. The homology of GS isotype gene promoter sequence among varieties with significant difference in grain protein content was over 99%, and the promoter sequence of GS isotype gene in intervarietal progeny could be changed. However, it did not cause changes in the core components of the promoter. The promoter of GS isotype gene is very conservative in the number and function of regulatory elements, and it is not easy to produce genetic variation in the structure and function of the promoter. The change of GS isotype gene expression was influenced by the regulation of GS gene promoter very little. The structure of GS isotype gene promoter was not completely consistent, and there were significant differences in the number of regulatory elements among different gene promoters. However, the promoter structure of GS isotype gene was consistent among different varieties. The expression and degree of GS isotype gene were related to many environmental factors.
【学位授予单位】：东北农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S511

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