小麦MADS-box基因TaAGL32的功能研究

发布时间：2018-06-09 22:49

本文选题：小麦 + MADS-box　；参考：《山东农业大学》2017年硕士论文

【摘要】：小麦是我国乃至全世界重要的粮食作物,它占到全球人口主食的40%以上。合适的抽穗时间对于小麦产量形成至关重要,研究小麦抽穗时间的调控基因可以为其遗传改良提供重要的参考资料。本研究从小麦中克隆了一个MADS-box基因,依据参考序列比对结果,命名为Triticum aestivum L.AGAMOUS-Like 32(TaAGL32),对其表达模式和生物学功能进行了初步探究。主要结果如下:(1)TaAGL32基因有三个拷贝,分别定位于7A、7B、7D染色体,基因组序列全长分别是1908bp、1912bp和1790bp。基因结构分析显示三个基因含有七个外显子和六个内含子。相应的CDS长度均为693bp,三者之间仅有22个SNP差异,基因可编码230个氨基酸。(2)TaAGL32蛋白均含有两个保守的结构域,分别是MEF2-like结构域和K-Box结构域,属于典型的MIKC型蛋白。进化树分析表明,TaAGL32基因与其祖先种相比具有进化保守性。TaAGL32蛋白亚细胞定位分析显示其定位于细胞核中。(3)qRT-PCR结果显示,TaAGL32基因在多个组织中均有表达,其中在根与茎中的表达量高,在小穗和小花中也有较高的表达。昼夜节律分析结果显示TaAGL32基因表现出昼夜节律性,即TaAGL32基因的表达随着光照时间增加而逐渐提高,并在光照12h后达到表达峰值,继续光照反而表达下调,并在光照结束时到达最低。(4)利用RNA干扰策略降低了TaAGL32基因在小麦中的表达。结果发现,转基因小麦在长日照条件下延迟抽穗5-7d,而在自然条件下转基因小麦与对照相比晚抽穗3-4d。该基因的四倍体小麦突变体也表现出晚抽穗的表型。这些结果表明TaAGL32基因在小麦抽穗过程可能起到调控作用。(5)对转基因小麦其他农艺性状的统计显示,转基因株系株高低于对照材料,两个株系分别比对照矮约4.1cm和2.2cm,差异显著;转基因株系的穗长也有显著地下降,与对照相比较短约1.5cm;小穗数目和千粒重有不同程度的降低,但是差异不明显。
[Abstract]:Wheat is an important food crop in China and the world. It accounts for more than 40% of the staple food in the world. The suitable heading time is very important for wheat yield formation, and the study of the regulating genes of wheat heading time can provide important references for its genetic improvement. In this study, a MADS-box gene was cloned from wheat and named Triticum aestivum L.AGAMOUS-Like 32 TaAGL32 according to the results of reference sequence alignment. The expression pattern and biological function of MADS-box gene were preliminarily studied. The main results are as follows: there are three copies of the TaAGL32 gene, which are located on chromosome 7A 7BN 7D respectively. The genome sequences are 1908 BP, 1912 BP and 1790 BP, respectively. Genetic analysis showed that three genes contained seven exons and six introns. The corresponding length of CDS is 693bp. there are only 22 SNP differences among them. The gene can encode 230 amino acids. TaAGL32 protein contains two conserved domains, namely MEF2-like domain and K-box domain, which belong to the typical MIKC-type protein. Phylogenetic tree analysis showed that the TaAGL32 gene was evolutionarily conserved compared with its ancestors. The subcellular localization analysis of TaAGL32 protein showed that it was located in the nucleus. The results of QRT-PCR showed that the TaAGL32 gene was expressed in many tissues, especially in the roots and stems. High expression was also found in spikelets and florets. The results of circadian rhythm analysis showed that TaAGL32 gene showed circadian rhythm, that is, the expression of TaAGL32 gene gradually increased with the increase of illumination time, and reached the peak after 12 hours of illumination, and then decreased with the light exposure. At the end of illumination, TaAGL32 gene expression in wheat was reduced by RNA interference. The results showed that the late heading of transgenic wheat was 3-4 days later than that of the control under the condition of long sunshine, but the late heading of transgenic wheat was 3-4 days later than that of the control under natural conditions. The tetraploid wheat mutant of the gene also showed late heading phenotype. These results indicated that TaAGL32 gene might play a regulatory role in the heading process of wheat. The statistics of other agronomic characters of transgenic wheat showed that the plant height of transgenic lines was lower than that of the control lines, and the difference between the two lines was significant compared with the control, about 4.1cm and 2.2 cm, respectively. The panicle length of transgenic lines also decreased significantly, which was about 1.5 cm shorter than that of the control, and the number of spikelets and 1000-grain weight decreased to some extent, but the difference was not significant.
【学位授予单位】：山东农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S512.1

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